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Leaf A, Rothschild JA, Sharpe TM, Sims ST, Macias CJ, Futch GG, Roberts MD, Stout JR, Ormsbee MJ, Aragon AA, Campbell BI, Arent SM, D’Agostino DP, Barrack MT, Kerksick CM, Kreider RB, Kalman DS, Antonio J. International society of sports nutrition position stand: ketogenic diets. J Int Soc Sports Nutr 2024; 21:2368167. [PMID: 38934469 PMCID: PMC11212571 DOI: 10.1080/15502783.2024.2368167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
POSITION STATEMENT The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the use of a ketogenic diet in healthy exercising adults, with a focus on exercise performance and body composition. However, this review does not address the use of exogenous ketone supplements. The following points summarize the position of the ISSN. 1. A ketogenic diet induces a state of nutritional ketosis, which is generally defined as serum ketone levels above 0.5 mM. While many factors can impact what amount of daily carbohydrate intake will result in these levels, a broad guideline is a daily dietary carbohydrate intake of less than 50 grams per day. 2. Nutritional ketosis achieved through carbohydrate restriction and a high dietary fat intake is not intrinsically harmful and should not be confused with ketoacidosis, a life-threatening condition most commonly seen in clinical populations and metabolic dysregulation. 3. A ketogenic diet has largely neutral or detrimental effects on athletic performance compared to a diet higher in carbohydrates and lower in fat, despite achieving significantly elevated levels of fat oxidation during exercise (~1.5 g/min). 4. The endurance effects of a ketogenic diet may be influenced by both training status and duration of the dietary intervention, but further research is necessary to elucidate these possibilities. All studies involving elite athletes showed a performance decrement from a ketogenic diet, all lasting six weeks or less. Of the two studies lasting more than six weeks, only one reported a statistically significant benefit of a ketogenic diet. 5. A ketogenic diet tends to have similar effects on maximal strength or strength gains from a resistance training program compared to a diet higher in carbohydrates. However, a minority of studies show superior effects of non-ketogenic comparators. 6. When compared to a diet higher in carbohydrates and lower in fat, a ketogenic diet may cause greater losses in body weight, fat mass, and fat-free mass, but may also heighten losses of lean tissue. However, this is likely due to differences in calorie and protein intake, as well as shifts in fluid balance. 7. There is insufficient evidence to determine if a ketogenic diet affects males and females differently. However, there is a strong mechanistic basis for sex differences to exist in response to a ketogenic diet.
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Affiliation(s)
- Alex Leaf
- Alex Leaf LLC, Scientific Affairs, Scottsdale, AZ, USA
| | - Jeffrey A. Rothschild
- Auckland University of Technology, Sports Performance Research Institute New Zealand, Auckland, New Zealand
- High Performance Sport New Zealand, Performance Nutrition, Auckland, New Zealand
| | - Tim M. Sharpe
- University of Western States, Human Nutrition and Functional Medicine, Portland, OR, USA
| | - Stacy T. Sims
- Auckland University of Technology, Sports Performance Research Institute New Zealand, Auckland, New Zealand
- Stanford University, Stanford Lifestyle Medicine, Palo Alto, CA, USA
| | - Chad J. Macias
- University of Western States, Human Nutrition and Functional Medicine, Portland, OR, USA
| | - Geoff G. Futch
- Springfield College, Department of Exercise Science and Athletic Training, Springfield, MA, USA
- FitPro Analytics, Scientific Affairs, Springfield, MA, USA
| | | | - Jeffrey R. Stout
- University of Central Florida, School of Kinesiology and Rehabilitation Sciences, Orlando, FL, USA
| | - Michael J. Ormsbee
- Florida State University, Institute of Sports Sciences & Medicine, Tallahassee, FL, USA
- University of KwaZulu Natal, Discipline of Biokinetics, Exercise and Leisure Sciences, Durban, South Africa
| | | | - Bill I. Campbell
- University of South Florida, Performance and Physique Enhancement Laboratory, Exercise Science Program, Tampa, FL, USA
| | - Shawn M. Arent
- University of South Carolina, Department of Exercise Science, Arnold School of Public Health, Columbia, SC, USA
| | - Dominic P. D’Agostino
- Institute for Human and Machine Cognition, Human Healthspan, Resilience, and Performance, Pensacola, FL, USA
- University of South Florida, Department of Molecular Pharmacology and Physiology, Tampa, FL, USA
| | - Michelle T. Barrack
- California State University, Department of Family and Consumer Sciences, Long Beach, CA, USA
| | - Chad M. Kerksick
- Lindenwood University, Exercise and Performance Nutrition Laboratory, College of Science, Technology, and Health, St. Charles, MO, USA
| | - Richard B. Kreider
- Texas A&M University, Exercise and Sport Nutrition Lab, Department of Kinesiology and Sports Management, College Station, TX, USA
| | - Douglas S. Kalman
- Nova Southeastern University, Department of Nutrition. Dr. Kiran C. Patel College of Osteopathic Medicine. Davie, FL, USA
| | - Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, FL, USA
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Szendi K, Murányi E, Hunter N, Németh B. Methodological Challenges and Confounders in Research on the Effects of Ketogenic Diets: A Literature Review of Meta-Analyses. Foods 2024; 13:248. [PMID: 38254549 PMCID: PMC10814162 DOI: 10.3390/foods13020248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/04/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Several meta-analyses have found a positive association between a popular type of "fad diet", ketogenic diets, and their effect on anthropometric and blood parameters. However, the non-specific inclusion criteria for meta-analyses may lead to incorrect conclusions. The aim of this literature review is to highlight the main confounders and methodological pitfalls of meta-analyses on ketogenic diets by inspecting the presence of key inclusion criteria. The PubMed, Embase, and Web of Science databases and the Cochrane Database of Systematic Reviews were searched for meta-analyses. Most meta-analyses did not define the essential parameters of a ketogenic diet (i.e., calories, macronutrient ratio, types of fatty acids, ketone bodies, etc.) as inclusion criteria. Of the 28 included meta-analyses, few addressed collecting real, re-measured nutritional data from the ketogenic diet and control groups in parallel with the pre-designed nutritional data. Most meta-analyses reported positive results in favor of ketogenic diets, which can result in erroneous conclusions considering the numerous methodological pitfalls and confounders. Well-designed clinical trials with comparable results and their meta-analyses are needed. Until then, medical professionals should not recommend ketogenic diets as a form of weight loss when other well-known dietary options have been shown to be healthy and effective.
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Affiliation(s)
- Katalin Szendi
- Department of Public Health Medicine, Medical School, University of Pécs, 7624 Pécs, Hungary
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Chung N. Impact of the ketogenic diet on body fat, muscle mass, and exercise performance: a review. Phys Act Nutr 2023; 27:1-7. [PMID: 38297470 PMCID: PMC10844723 DOI: 10.20463/pan.2023.0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/12/2023] [Accepted: 11/17/2023] [Indexed: 02/02/2024] Open
Abstract
PURPOSE The purpose of this review was to investigate the effects of the ketogenic diet (KD), on body fat, muscle mass, and exercise performance. As the KD is a subject of ongoing debate, we also present the existing evidence regarding its potential benefits in the aforementioned areas of body fat, muscle mass, and exercise performance. METHODS A literature search was conducted using the keywords "ketogenic diet, low-carbohydrate diet, high-fat diet, body fat, muscle mass, and exercise performance" in PubMed, Web of Science, and Google Scholar. RESULTS The KD effectively reduced body fat in the short term and, preserved muscle mass during weight loss, however, its impact on exercise performance remains inconclusive owing to various factors. CONCLUSION While controversial, it is undeniable that the KD has the potential to affect body fat, muscle mass, and exercise performance. Consequently, additional research is required to elucidate the underlying mechanisms across various populations, optimize their implementation, and understand their long-term effects.
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Affiliation(s)
- Nana Chung
- Department of Physical Education, Sangji University, Wonju, Republic of Korea
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Frączek B, Pięta A. Does the Paleo diet affect an athlete's health and sport performance? Biol Sport 2023; 40:1125-1139. [PMID: 37867746 PMCID: PMC10588572 DOI: 10.5114/biolsport.2023.123325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 09/24/2022] [Accepted: 12/16/2022] [Indexed: 10/24/2023] Open
Abstract
The aim of the study was to assess the impact of an eight-week Paleo diet on the health status (body composition, haematology and biochemistry of blood and urine) and the level of physical capacity (aerobic and anaerobic) of professional handball players. Fifteen athletes were assigned to two groups: 9 in the experimental group (PD) and 6 in the control group (CD). Significant decreases in body mass (BM), body mass index (BMI), and fat mass (FM) as well as an increase in the fat-free mass (FFM) (%) in both groups were observed. There were no significant differences between groups in particular series during the experiment in all haematological and biochemical indicators of blood and urine. Only HDL-C was significantly higher in the last series in the PD compared to the CD (1.63 mmol/l vs. 1.23 mmol/l). In the Wingate test, there were only single intragroup changes, consisting of a significant decrease in the Wt, MAP and Pmean in the experimental group. There were no significant differences between the groups in individual series or intragroup differences during the experiment, determined by the VO2max, VEmax, VE ∙ VCO2 -1, RER, and the time of the test with a gradually increasing load on a treadmill, except for a significant decrease of maximum tidal volume (TVmax) in the PD. No adverse effect of the Paleo diet on the health status was found. The use of the Paleo diet slightly adversely affects anaerobic capacity and does not affect the level of aerobic capacity.
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Affiliation(s)
- Barbara Frączek
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Kraków, Poland
| | - Aleksandra Pięta
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Kraków, Poland
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Hsu C, Huang YW, Lin SM, Lu CS, Chen CY, Chang CK. Low- or moderate-carbohydrate calorie-restricted diets have similar effects on body composition and taekwondo performance after high-carbohydrate recovery meals. Eur J Sport Sci 2023; 23:1983-1992. [PMID: 37010257 DOI: 10.1080/17461391.2023.2199423] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Low-carbohydrate (LC) diets are popular among general and athletic populations attempting to lose body mass. This study investigated the effect of a 7-day LC or moderate-carbohydrate (MC) calorie-restricted diet followed by 18-h recovery on body composition and taekwondo-specific performance. In this randomised cross-over study, 12 male taekwondo athletes consumed an LC (10% of carbohydrate, 41% of protein, 49% of fat, and 15.8 ± 0.4 kcal/kg/day) or an isocaloric MC diet (60% of carbohydrate, 30% of protein, and 10% of fat) for 7 days. The participants then consumed a carbohydrate-rich recovery dinner (39.2 ± 3.1 kcal/kg) followed by breakfast (6.2 ± 0.4 kcal/kg) in both the trials. Three repeated sprint ability (RSA) tests were conducted after breakfast. The taekwondo-specific reaction battery was administered before the first RSA test and after each RSA test. The participants experienced similar magnitudes of significant loss of body mass in the LC (-2.4 ± 1.7%) and MC (-2.3 ± 1.7%) trials. Fat mass and fat percentage significantly decreased in the MC trial but remained unchanged in the LC trial after body mass loss. Fat free mass was maintained in both the trials. The average and peak power in the RSA tests and the premotor reaction time were similar between the trials. The participants experienced significantly higher fatigue in the LC trial. In conclusion, both the diets can help athletes rapidly lose body mass while maintaining performance as long as an adequate amount of carbohydrate is consumed during the recovery period.
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Affiliation(s)
- Chin Hsu
- Department of Exercise Health Science, National Taiwan University of Sport, Taichung, Taiwan
| | - Yun-Wen Huang
- Department of Sport Performance, National Taiwan University of Sport, Taichung, Taiwan
| | - Shu-Mei Lin
- Department of Nutrition, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan
| | - Ching-Shih Lu
- Department of Nutrition, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan
| | - Chung-Yu Chen
- Department of Physical Education, National Taiwan University of Sport, Taichung, Taiwan
| | - Chen-Kang Chang
- Department of Sport Performance, National Taiwan University of Sport, Taichung, Taiwan
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6
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Kaufman M, Nguyen C, Shetty M, Oppezzo M, Barrack M, Fredericson M. Popular Dietary Trends' Impact on Athletic Performance: A Critical Analysis Review. Nutrients 2023; 15:3511. [PMID: 37630702 PMCID: PMC10460072 DOI: 10.3390/nu15163511] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND Nutrition fuels optimal performance for athletes. With increased research developments, numerous diets available, and publicity from professional athletes, a review of dietary patterns impact on athletic performance is warranted. RESULTS The Mediterranean diet is a low inflammatory diet linked to improved power and muscle endurance and body composition. Ketogenic diets are restrictive of carbohydrates and proteins. Though both show no decrements in weight loss, ketogenic diets, which is a more restrictive form of low-carbohydrate diets, can be more difficult to follow. High-protein and protein-paced versions of low-carbohydrate diets have also shown to benefit athletic performance. Plant-based diets have many variations. Vegans are at risk of micronutrient deficiencies and decreased leucine content, and therefore, decreased muscle protein synthesis. However, the literature has not shown decreases in performance compared to omnivores. Intermittent fasting has many different versions, which may not suit those with comorbidities or specific needs as well as lead to decreases in sprint speed and worsening time to exhaustion. CONCLUSIONS This paper critically evaluates the research on diets in relation to athletic performance and details some of the potential risks that should be monitored. No one diet is universally recommend for athletes; however, this article provides the information for athletes to analyze, in conjunction with medical professional counsel, their own diet and consider sustainable changes that can help achieve performance and body habitus goals.
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Affiliation(s)
- Matthew Kaufman
- Department of Orthopaedic Surgery, Stanford University, Redwood City, CA 94063, USA
| | - Chantal Nguyen
- Department of Orthopaedic Surgery, Stanford University, Redwood City, CA 94063, USA
| | - Maya Shetty
- Department of Orthopaedic Surgery, Stanford University, Redwood City, CA 94063, USA
| | - Marily Oppezzo
- Prevention Research Center, Stanford University, Redwood City, CA 94063, USA
| | - Michelle Barrack
- Department of Family and Consumer Sciences, California State University, Long Beach, CA 90840, USA
| | - Michael Fredericson
- Department of Orthopaedic Surgery, Stanford University, Redwood City, CA 94063, USA
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Effect of Time-Restricted Eating and Resistance Training on High-Speed Strength and Body Composition. Nutrients 2023; 15:nu15020285. [PMID: 36678156 PMCID: PMC9863948 DOI: 10.3390/nu15020285] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 01/09/2023] Open
Abstract
This study examined the effects of four weeks of resistance training combined with time-restricted eating (TRE) vs. habitual diet on fat and fat-free mass as well as maximum and explosive force production in healthy, trained participants (18 males, aged 23.7 ± 2.6 years). The order of dieting was randomized and counterbalanced, and the participants served as their own controls. TRE involved an 8-h eating window and non-TRE involved a habitual meal pattern. Participants completed performance strength tests and body composition scans at baseline and post-intervention. The participants followed a structured training routine during each dietary intervention (four sets of maximum repetitions at 85% 1RM in five dynamic exercises, three times/week). Both interventions elicited deceases in fat mass (p < 0.05) but not in fat-free mass. After training (controlling for baseline values as covariates), non-TRE was compatible with better lower body jump performance than TRE (p < 0.05). Conversely, training with TRE elicited higher values in terms of peak force and dynamic strength index at the level of the upper body (p < 0.05). Thus, it can be concluded that there were no differences in fat mass and fat-free mass changes between interventions in already trained young males. Additionally, while the combination of TRE and resistance training might be beneficial for individuals focusing on developing high-speed strength performance at the upper body level, this is not applicable to those focusing on training the lower body.
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8
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Vargas-Molina S, Gómez-Urquiza JL, García-Romero J, Benítez-Porres J. Effects of the Ketogenic Diet on Muscle Hypertrophy in Resistance-Trained Men and Women: A Systematic Review and Meta-Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph191912629. [PMID: 36231929 PMCID: PMC9564904 DOI: 10.3390/ijerph191912629] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/25/2022] [Accepted: 09/30/2022] [Indexed: 05/22/2023]
Abstract
Reviews focused on the ketogenic diet (KD) based on the increase in fat-free mass (FFM) have been carried out with pathological populations or, failing that, without population differentiation. The aim of this review and meta-analysis was to verify whether a ketogenic diet without programmed energy restriction generates increases in fat-free mass (FFM) in resistance-trained participants. We evaluated the effect of the ketogenic diet, in conjunction with resistance training, on fat-free mass in trained participants. Boolean algorithms from various databases (PubMed, Scopus. and Web of Science) were used, and a total of five studies were located that related to both ketogenic diets and resistance-trained participants. In all, 111 athletes or resistance-trained participants (87 male and 24 female) were evaluated in the studies analyzed. We found no significant differences between groups in the FFM variables, and more research is needed to perform studies with similar ketogenic diets and control diet interventions. Ketogenic diets, taking into account the possible side effects, can be an alternative for increasing muscle mass as long as energy surplus is generated; however, their application for eight weeks or more without interruption does not seem to be the best option due to the satiety and lack of adherence generated.
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Affiliation(s)
- Salvador Vargas-Molina
- Department of Physical Education and Sport, Faculty of Sport Sciences, EADE-University of Wales Trinity Saint David, 29018 Málaga, Spain
- Physical Education and Sports Area, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
| | - José L. Gómez-Urquiza
- Department of Nursing, Faculty of Health Sciences, University of Granada, 18071 Granada, Spain
| | - Jerónimo García-Romero
- Physical Education and Sports Area, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
| | - Javier Benítez-Porres
- Physical Education and Sports Area, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Correspondence:
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Defeudis G, Rossini M, Khazrai YM, Pipicelli AMV, Brucoli G, Veneziano M, Strollo F, Bellia A, Bitterman O, Lauro D, Mora D, Santarelli E. The gut microbiome as possible mediator of the beneficial effects of very low calorie ketogenic diet on type 2 diabetes and obesity: a narrative review. Eat Weight Disord 2022; 27:2339-2346. [PMID: 35773554 DOI: 10.1007/s40519-022-01434-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 06/11/2022] [Indexed: 10/17/2022] Open
Abstract
Several studies have shown a strong correlation between the different types of diets and gut microbiota composition on glycemia and weight loss. In this direction, low-carbohydrate and ketogenic diets have gained popularity, despite studies published so far leading to controversial results on subjects with diabetes. In this narrative review, firstly, we aimed to analyze the role of very-low-calorie ketogenic diets (VLCKDs) in type 2 diabetes (T2DM) and obesity management. Secondly, in this context, we focused attention on gut microbiota as a function of VLCKD, particularly in T2DM and obesity treatment. Finally, we reported all this evidence to underline the importance of gut microbiota to exalt new nutritional strategies for "tailor-made" management, treatment, and rehabilitation in subjects with T2DM and obesity, even with diabetic complications. In conclusion, this narrative review outlined the beneficial impact of VLCKD on gut microbiota even in subjects with T2DM and obesity, and, despite inner VLCKD short-duration feature allowing no sound-enough provisions for long-term outcomes, witnessed in favor of the short-term safety of VLCKD in those patients.Level of evidence Level V: Opinions of authorities, based on descriptive studies, narrative reviews, clinical experience, or reports of expert committees.
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Affiliation(s)
- G Defeudis
- Unit of Endocrinology and Diabetes, Department of Medicine, University Campus Bio-Medico di Roma, Rome, Italy.
| | - M Rossini
- Diet and Diabetes Unit, ASL RM1, Rome, Italy
| | - Y M Khazrai
- Unit of Food Science and Nutrition, Department of Science and Technology for Humans and the Environment, University Campus Bio-Medico di Roma, Rome, Italy
| | - A M V Pipicelli
- UOC di Nefrologia, Dialisi e Trapianto, Dipartimento di Scienze Mediche e Chirurgiche, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - G Brucoli
- Diet and Diabetes Unit, ASL RM1, Rome, Italy
| | - M Veneziano
- Diet and Diabetes Unit, ASL RM1, Rome, Italy
| | - F Strollo
- Endocrinology and Diabetes Unit, IRCCS San Raffaele Pisana, Rome, Italy
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Dietary Risk Factors and Eating Behaviors in Peripheral Arterial Disease (PAD). Int J Mol Sci 2022; 23:ijms231810814. [PMID: 36142725 PMCID: PMC9504787 DOI: 10.3390/ijms231810814] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.
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Abstract
Obesity remains a serious relevant public health concern throughout the world despite related countermeasures being well understood (i.e. mainly physical activity and an adjusted diet). Among different nutritional approaches, there is a growing interest in ketogenic diets (KD) to manipulate body mass (BM) and to enhance fat mass loss. KD reduce the daily amount of carbohydrate intake drastically. This results in increased fatty acid utilisation, leading to an increase in blood ketone bodies (acetoacetate, 3-β-hydroxybutyrate and acetone) and therefore metabolic ketosis. For many years, nutritional intervention studies have focused on reducing dietary fat with little or conflicting positive results over the long term. Moreover, current nutritional guidelines for athletes propose carbohydrate-based diets to augment muscular adaptations. This review discusses the physiological basis of KD and their effects on BM reduction and body composition improvements in sedentary individuals combined with different types of exercise (resistance training or endurance training) in individuals with obesity and athletes. Ultimately, we discuss the strengths and the weaknesses of these nutritional interventions together with precautionary measures that should be observed in both individuals with obesity and athletic populations. A literature search from 1921 to April 2021 using Medline, Google Scholar, PubMed, Web of Science, Scopus and Sportdiscus Databases was used to identify relevant studies. In summary, based on the current evidence, KD are an efficient method to reduce BM and body fat in both individuals with obesity and athletes. However, these positive impacts are mainly because of the appetite suppressive effects of KD, which can decrease daily energy intake. Therefore, KD do not have any superior benefits to non-KD in BM and body fat loss in individuals with obesity and athletic populations in an isoenergetic situation. In sedentary individuals with obesity, it seems that fat-free mass (FFM) changes appear to be as great, if not greater, than decreases following a low-fat diet. In terms of lean mass, it seems that following a KD can cause FFM loss in resistance-trained individuals. In contrast, the FFM-preserving effects of KD are more efficient in endurance-trained compared with resistance-trained individuals.
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Zdzieblik D, Friesenborg H, Gollhofer A, König D. Effect of a High Fat Diet vs. High Carbohydrate Diets With Different Glycemic Indices on Metabolic Parameters in Male Endurance Athletes: A Pilot Trial. Front Nutr 2022; 9:802374. [PMID: 35479739 PMCID: PMC9037589 DOI: 10.3389/fnut.2022.802374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/04/2022] [Indexed: 12/20/2022] Open
Abstract
Consuming low glycemic carbohydrates leads to an increased muscle fat utilization and preservation of intramuscular glycogen, which is associated with improved flexibility to metabolize either carbohydrates or fats during endurance exercise. The purpose of this trial was to investigate the effect of a 4-week high fat low carbohydrate (HFLC-G: ≥65% high glycemic carbohydrates per day; n = 9) vs. high carbohydrate low glycemic (LGI-G: ≥65% low glycemic carbohydrates daily; n = 10) or high glycemic (HGI-G: ≥65% fat, ≤ 50 g carbohydrates daily; n = 9) diet on fat and carbohydrate metabolism at rest and during exercise in 28 male athletes. Changes in metabolic parameters under resting conditions and during cycle ergometry (submaximal and with incremental workload) from pre- to post-intervention were determined by lactate diagnostics and measurements of the respiratory exchange ratio (RER). Additionally, body composition and perceptual responses to the diets [visual analog scale (VAS)] were measured. A significance level of α = 0.05 was considered. HFLC-G was associated with markedly decreased lactate concentrations during the submaximal (−0.553 ± 0.783 mmol/l, p = 0.067) and incremental cycle test [−5.00 ± 5.71 (mmol/l) × min; p = 0.030] and reduced RER values at rest (−0.058 ± 0.108; p = 0.146) during the submaximal (−0.078 ± 0.046; p = 0.001) and incremental cycle test (−1.64 ± 0.700 RER × minutes; p < 0.001). In the HFLC-G, fat mass (p < 0.001) decreased. In LGI-G lactate, concentrations decreased in the incremental cycle test [−6.56 ± 6.65 (mmol/l) × min; p = 0.012]. In the LGI-G, fat mass (p < 0.01) and VAS values decreased, indicating improved levels of gastrointestinal conditions and perception of effort during training. The main findings in the HGI-G were increased RER (0.047 ± 0.076; p = 0.117) and lactate concentrations (0.170 ± 0.206 mmol/l, p = 0.038) at rest. Although the impact on fat oxidation in the LGI-G was not as pronounced as following the HFLC diet, the adaptations in the LGI-G were consistent with an improved metabolic flexibility and additional benefits regarding exercise performance in male athletes.
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Affiliation(s)
- Denise Zdzieblik
- Department for Nutrition, Institute for Sports and Sports Science, University of Freiburg, Freiburg, Germany
| | - Hilke Friesenborg
- Department for Nutrition, Institute for Sports and Sports Science, University of Freiburg, Freiburg, Germany
| | - Albert Gollhofer
- Department for Nutrition, Institute for Sports and Sports Science, University of Freiburg, Freiburg, Germany
| | - Daniel König
- Centre for Sports Science and University Sports, Department for Nutrition, Exercise and Health, University of Vienna, Vienna, Austria.,Department for Nutrition, Exercise and Health, Faculty of Life Sciences, University of Vienna, Vienna, Austria
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13
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Saito H, Wada N, Iida K. Isonitrogenous low-carbohydrate diet elicits specific changes in metabolic gene expression in the skeletal muscle of exercise-trained mice. PLoS One 2022; 17:e0262875. [PMID: 35061842 PMCID: PMC8782354 DOI: 10.1371/journal.pone.0262875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 01/06/2022] [Indexed: 11/28/2022] Open
Abstract
With the renewed interest in low-carbohydrate diets (LCDs) in the sports field, a few animal studies have investigated their potential. However, most rodent studies have used an LCD containing low protein, which does not recapitulate a human LCD, and the muscle-specific adaptation in response to an LCD remains unclear. Therefore, we investigated the effects of two types of LCDs, both containing the same proportion of protein as a regular diet (isonitrogenous LCD; INLCD), on body composition, exercise performance, and metabolic fuel selection at the genetic level in the skeletal muscles of exercise-trained mice. Three groups of mice (n = 8 in each group), one fed a regular AIN-93G diet served as the control, and the others fed either of the two INLCDs containing 20% protein and 10% carbohydrate (INLCD-10%) or 20% protein and 1% carbohydrate (INLCD-1%) had a regular exercise load (5 times/week) for 12 weeks. Body weight and muscle mass did not decrease in either of the INLCD-fed groups, and the muscle glycogen levels and endurance capacity did not differ among the three groups. Only in the mice fed INLCD-1% did the plasma ketone concentration significantly increase, and gene expression related to glucose utilization significantly declined in the muscles. Both INLCD-1% and INLCD-10% consumption increased gene expression related to lipid utilization. These results suggest that, although INLCD treatment did not affect endurance capacity, it helped maintain muscle mass and glycogen content regardless of the glucose intake restrictions in trained mice. Moreover, an INLCD containing a low carbohydrate content might present an advantage by increasing lipid oxidation without ketosis and suppressing muscle glucose utilization.
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Affiliation(s)
- Hazuki Saito
- Department of Food and Nutrition Science, Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo, Tokyo, Japan
| | - Naoko Wada
- Department of Food and Nutrition Science, Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo, Tokyo, Japan
| | - Kaoruko Iida
- Department of Food and Nutrition Science, Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo, Tokyo, Japan
- The Institute for Human Life Innovation, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo, Japan
- * E-mail:
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14
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Henselmans M, Bjørnsen T, Hedderman R, Vårvik FT. The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review. Nutrients 2022; 14:nu14040856. [PMID: 35215506 PMCID: PMC8878406 DOI: 10.3390/nu14040856] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 12/04/2022] Open
Abstract
High carbohydrate intakes are commonly recommended for athletes of various sports, including strength trainees, to optimize performance. However, the effect of carbohydrate intake on strength training performance has not been systematically analyzed. A systematic literature search was conducted for trials that manipulated carbohydrate intake, including supplements, and measured strength, resistance training or power either acutely or after a diet and strength training program. Studies were categorized as either (1) acute supplementation, (2) exercise-induced glycogen depletion with subsequent carbohydrate manipulation, (3) short-term (2–7 days) carbohydrate manipulation or (4) changes in performance after longer-term diet manipulation and strength training. Forty-nine studies were included: 19 acute, six glycogen depletion, seven short-term and 17 long-term studies. Participants were strength trainees or athletes (39 studies), recreationally active (six studies) or untrained (four studies). Acutely, higher carbohydrate intake did not improve performance in 13 studies and enhanced performance in six studies, primarily in those with fasted control groups and workouts with over 10 sets per muscle group. One study found that a carbohydrate meal improved performance compared to water but not in comparison to a sensory-matched placebo breakfast. There was no evidence of a dose-response effect. After glycogen depletion, carbohydrate supplementation improved performance in three studies compared to placebo, in particular during bi-daily workouts, but not in research with isocaloric controls. None of the seven short-term studies found beneficial effects of carbohydrate manipulation. Longer-term changes in performance were not influenced by carbohydrate intake in 15 studies; one study favored the higher- and one the lower-carbohydrate condition. Carbohydrate intake per se is unlikely to strength training performance in a fed state in workouts consisting of up to 10 sets per muscle group. Performance during higher volumes may benefit from carbohydrates, but more studies with isocaloric control groups, sensory-matched placebos and locally measured glycogen depletion are needed.
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Affiliation(s)
- Menno Henselmans
- The International Scientific Research Foundation for Fitness and Nutrition, David Blesstraat 28HS, 1073 LC Amsterdam, The Netherlands; (R.H.); (F.T.V.)
- Correspondence: ; Tel.: +31-61-809-5999
| | - Thomas Bjørnsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway;
| | - Richie Hedderman
- The International Scientific Research Foundation for Fitness and Nutrition, David Blesstraat 28HS, 1073 LC Amsterdam, The Netherlands; (R.H.); (F.T.V.)
| | - Fredrik Tonstad Vårvik
- The International Scientific Research Foundation for Fitness and Nutrition, David Blesstraat 28HS, 1073 LC Amsterdam, The Netherlands; (R.H.); (F.T.V.)
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway;
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15
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Noakes TD. What Is the Evidence That Dietary Macronutrient Composition Influences Exercise Performance? A Narrative Review. Nutrients 2022; 14:862. [PMID: 35215511 PMCID: PMC8875928 DOI: 10.3390/nu14040862] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 01/06/2023] Open
Abstract
The introduction of the needle muscle biopsy technique in the 1960s allowed muscle tissue to be sampled from exercising humans for the first time. The finding that muscle glycogen content reached low levels at exhaustion suggested that the metabolic cause of fatigue during prolonged exercise had been discovered. A special pre-exercise diet that maximized pre-exercise muscle glycogen storage also increased time to fatigue during prolonged exercise. The logical conclusion was that the athlete's pre-exercise muscle glycogen content is the single most important acutely modifiable determinant of endurance capacity. Muscle biochemists proposed that skeletal muscle has an obligatory dependence on high rates of muscle glycogen/carbohydrate oxidation, especially during high intensity or prolonged exercise. Without this obligatory carbohydrate oxidation from muscle glycogen, optimum muscle metabolism cannot be sustained; fatigue develops and exercise performance is impaired. As plausible as this explanation may appear, it has never been proven. Here, I propose an alternate explanation. All the original studies overlooked one crucial finding, specifically that not only were muscle glycogen concentrations low at exhaustion in all trials, but hypoglycemia was also always present. Here, I provide the historical and modern evidence showing that the blood glucose concentration-reflecting the liver glycogen rather than the muscle glycogen content-is the homeostatically-regulated (protected) variable that drives the metabolic response to prolonged exercise. If this is so, nutritional interventions that enhance exercise performance, especially during prolonged exercise, will be those that assist the body in its efforts to maintain the blood glucose concentration within the normal range.
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Affiliation(s)
- Timothy David Noakes
- Department of Applied Design, Cape Peninsula University of Technology, Cape Town 8000, South Africa
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16
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Ruiz-Castellano C, Espinar S, Contreras C, Mata F, Aragon AA, Martínez-Sanz JM. Achieving an Optimal Fat Loss Phase in Resistance-Trained Athletes: A Narrative Review. Nutrients 2021; 13:nu13093255. [PMID: 34579132 PMCID: PMC8471721 DOI: 10.3390/nu13093255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 12/14/2022] Open
Abstract
Managing the body composition of athletes is a common practice in the field of sports nutrition. The loss of body weight (BW) in resistance-trained athletes is mainly conducted for aesthetic reasons (bodybuilding) or performance (powerlifting or weightlifting). The aim of this review is to provide dietary–nutritional strategies for the loss of fat mass in resistance-trained athletes. During the weight loss phase, the goal is to reduce the fat mass by maximizing the retention of fat-free mass. In this narrative review, the scientific literature is evaluated, and dietary–nutritional and supplementation recommendations for the weight loss phase of resistance-trained athletes are provided. Caloric intake should be set based on a target BW loss of 0.5–1.0%/week to maximize fat-free mass retention. Protein intake (2.2–3.0 g/kgBW/day) should be distributed throughout the day (3–6 meals), ensuring in each meal an adequate amount of protein (0.40–0.55 g/kgBW/meal) and including a meal within 2–3 h before and after training. Carbohydrate intake should be adapted to the level of activity of the athlete in order to training performance (2–5 g/kgBW/day). Caffeine (3–6 mg/kgBW/day) and creatine monohydrate (3–5 g/day) could be incorporated into the athlete’s diet due to their ergogenic effects in relation to resistance training. The intake of micronutrients complexes should be limited to special situations in which there is a real deficiency, and the athlete cannot consume through their diet.
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Affiliation(s)
| | - Sergio Espinar
- Faculty of Health Sciences, UCAM Universidad Católica de Murcia, 30107 Murcia, Spain;
- Correspondence:
| | - Carlos Contreras
- Faculty of Health Sciences, UCAM Universidad Católica de Murcia, 30107 Murcia, Spain;
| | - Fernando Mata
- Centro de Estudios Avanzados en Nutrición (CEAN), 14010 Córdoba, Spain;
| | - Alan A. Aragon
- Department of Family and Consumer Sciences, California State University, Northridge, CA 91330, USA;
| | - José Miguel Martínez-Sanz
- Research Group on Food and Nutrition (ALINUT), Nursing Department, Faculty of Health Sciences, University of Alicante, 03690 Alicante, Spain;
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17
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Antonio Paoli A, Mancin L, Caprio M, Monti E, Narici MV, Cenci L, Piccini F, Pincella M, Grigoletto D, Marcolin G. Effects of 30 days of ketogenic diet on body composition, muscle strength, muscle area, metabolism, and performance in semi-professional soccer players. J Int Soc Sports Nutr 2021; 18:62. [PMID: 34530857 PMCID: PMC8447662 DOI: 10.1186/s12970-021-00459-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/25/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND A ketogenic diet (KD) is a nutritional approach, usually adopted for weight loss, that restricts daily carbohydrates under 30 g/day. KD showed contradictory results on sport performance, whilst no data are available on team sports. We sought to investigate the influence of a KD on different parameters in semi-professional soccer players. METHODS Subjects were randomly assigned to a iso-protein (1.8 g/Kg body weight/day) ketogenic diet (KD) or western diet (WD) for 30 days. Body weight and body composition, resting energy expenditure (REE), respiratory exchange ratio (RER), cross sectional area (CSA) and isometric muscle strength of quadriceps, counter movement jump (CMJ) and yoyo intermittent recovery test time were measured. RESULTS There was a significantly higher decrease of body fat (p = 0.0359), visceral adipose tissue (VAT) (p = 0.0018), waist circumference (p = 0.0185) and extra-cellular water (p = 0.0060) in KD compared to WD group. Lean soft tissue, quadriceps muscle area, maximal strength and REE showed no changes in both groups. RER decreased significantly in KD (p = 0.0008). Yo-yo intermittent test improved significantly (p < 0.0001) in both groups without significant differences between groups. CMJ significantly improved (p = 0.0021) only in KD. CONCLUSIONS This is the first study investigating the effects of a KD on semi-professional soccer players. In our study KD athletes lost fat mass without any detrimental effects on strength, power and muscle mass. When the goal is a rapid weight reduction in such athletes, the use of a KD should be taken into account. TRIAL REGISTRATION registered retrospectively on Clinical Trial registration number NCT04078971 .
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Affiliation(s)
- A Antonio Paoli
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, 35131, Padua, Italy. .,Research Center for High Performance Sport, UCAM, Catholic University of Murcia, 30107, Murcia, Spain. .,Human Inspired Technology Research Center, University of Padua, Padua, Italy.
| | - Laura Mancin
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, 35131, Padua, Italy.,Human Inspired Technology Research Center, University of Padua, Padua, Italy
| | - Massimiliano Caprio
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, Rome, Italy
| | - Elena Monti
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, 35131, Padua, Italy
| | - Marco V Narici
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, 35131, Padua, Italy
| | - Lorenzo Cenci
- Human Inspired Technology Research Center, University of Padua, Padua, Italy
| | | | - Matteo Pincella
- Inter FC., Milan, Italy.,FIGC Federazione Italiana Giuoco Calcio (Italian Football Federation), Rome, Italy
| | - Davide Grigoletto
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, 35131, Padua, Italy
| | - Giuseppe Marcolin
- Department of Biomedical Sciences, University of Padua, Via Marzolo, 3, 35131, Padua, Italy
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18
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Valenzuela PL, Castillo-García A, Lucia A, Naclerio F. Effects of Combining a Ketogenic Diet with Resistance Training on Body Composition, Strength, and Mechanical Power in Trained Individuals: A Narrative Review. Nutrients 2021; 13:nu13093083. [PMID: 34578961 PMCID: PMC8469041 DOI: 10.3390/nu13093083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/11/2021] [Accepted: 08/30/2021] [Indexed: 01/20/2023] Open
Abstract
Ketogenic diets (KD) have gained popularity in recent years among strength-trained individuals. The present review summarizes current evidence—with a particular focus on randomized controlled trials—on the effects of KD on body composition and muscle performance (strength and power output) in strength-trained individuals. Although long-term studies (>12 weeks) are lacking, growing evidence supports the effectiveness of an ad libitum and energy-balanced KD for reducing total body and fat mass, at least in the short term. However, no or negligible benefits on body composition have been observed when comparing hypocaloric KD with conventional diets resulting in the same energy deficit. Moreover, some studies suggest that KD might impair resistance training-induced muscle hypertrophy, sometimes with concomitant decrements in muscle performance, at least when expressed in absolute units and not relative to total body mass (e.g., one-repetition maximum). KD might therefore be a beneficial strategy for promoting fat loss, although it might not be a recommendable option to gain muscle mass and strength/power. More research is needed on the adoption of strategies for avoiding the potentially detrimental effect of KD on muscle mass and strength/power (e.g., increasing protein intake, reintroduction of carbohydrates before competition). In summary, evidence is as yet scarce to support a major beneficial effect of KD on body composition or performance in strength-trained individuals. Furthermore, the long-term effectiveness and safety of this type of diet remains to be determined.
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Affiliation(s)
- Pedro L. Valenzuela
- Faculty of Sport Sciences, Universidad Europea de Madrid, 28670 Madrid, Spain; (P.L.V.); (A.L.)
| | | | - Alejandro Lucia
- Faculty of Sport Sciences, Universidad Europea de Madrid, 28670 Madrid, Spain; (P.L.V.); (A.L.)
- Physical Activity and Health Research Group (‘PaHerg’), Research Institute of the Hospital 12 de Octubre (‘imas12’), 28041 Madrid, Spain
| | - Fernando Naclerio
- Institute for Lifecourse Development, School of Human Sciences, Centre for Exercise Activity and Rehabilitation, University of Greenwich, London SE10 9LS, UK
- Correspondence: or
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19
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Cao J, Lei S, Wang X, Cheng S. The Effect of a Ketogenic Low-Carbohydrate, High-Fat Diet on Aerobic Capacity and Exercise Performance in Endurance Athletes: A Systematic Review and Meta-Analysis. Nutrients 2021; 13:nu13082896. [PMID: 34445057 PMCID: PMC8400555 DOI: 10.3390/nu13082896] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/02/2021] [Accepted: 08/19/2021] [Indexed: 12/29/2022] Open
Abstract
A low-carbohydrate, high-fat (LCHF) diet has been proposed to enhance the fat utilization of muscle and the aerobic capacity of endurance athletes, thereby improving their exercise performance. However, it remains uncertain how the macronutrient intake shift from carbohydrate to fat affects endurance exercise training and performance. This study performed a systematic review and meta-analysis to explore the effects of a ketogenic low-carbohydrate, high-fat (K-LCHF) diet on aerobic capacity and exercise performance among endurance athletes. Searches were carried out in five electronic databases, and we followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The search included studies using an LCHF diet as an intervention protocol and compared data on factors such as maximum oxygen uptake (VO2max) and rating of perceived exertion (RPE) from the graded exercise test. In this case, 10 studies met the criteria and were included in the meta-analysis. We did not find a significant effect of K-LCHF diet interventions on VO2max, time to exhaustion, HRmax or RPE. However, a significant overall effect in the substrate oxidation response to respiratory exchange rate was observed. The meta-analysis showed that K-LCHF diets did not affect aerobic capacity and exercise performance. Therefore, high-quality interventions of a K-LCHF diet are needed to illustrate its effect on various endurance training programs.
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Affiliation(s)
- Jingguo Cao
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai 200240, China; (J.C.); (S.L.); (S.C.)
| | - Siman Lei
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai 200240, China; (J.C.); (S.L.); (S.C.)
- Faculty of Education, University of Macau, Macau SAR, China
| | - Xiuqiang Wang
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai 200240, China; (J.C.); (S.L.); (S.C.)
- Exercise Translational Medicine Centre, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
- Correspondence:
| | - Sulin Cheng
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai 200240, China; (J.C.); (S.L.); (S.C.)
- Exercise Translational Medicine Centre, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
- Faculty of Sport and Health Science, University of Jyväskylä, 40014 Jyväskylä, Finland
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20
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The Effects of Fasting or Ketogenic Diet on Endurance Exercise Performance and Metabolism in Female Mice. Metabolites 2021; 11:metabo11060397. [PMID: 34207054 PMCID: PMC8234851 DOI: 10.3390/metabo11060397] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 01/13/2023] Open
Abstract
The promotion of ketone body (KB) metabolism via ketosis has been suggested as a strategy to increase exercise performance. However, studies in humans and animals have yielded inconsistent results. The purpose of the current study was to examine the effects of ketosis, achieved via fasting or a short-term ketogenic diet (KD), on endurance exercise performance in female mice. After 8 h of fasting, serum KB significantly increased and serum glucose significantly decreased in fasted compared to fed mice. When subjected to an endurance exercise capacity (EEC) test on a motorized treadmill, both fed and fasted mice showed similar EEC performance. A 5-week KD (90% calories from fat) significantly increased serum KB but did not increase EEC times compared to chow-fed mice. KD mice gained significantly more weight than chow-fed mice and had greater adipose tissue mass. Biochemical tissue analysis showed that KD led to significant increases in triglyceride content in the heart and liver and significant decreases in glycogen content in the muscle and liver. Furthermore, KD downregulated genes involved in glucose and KB oxidation and upregulated genes involved in lipid metabolism in the heart. These findings suggest that a short-term KD is not an effective strategy to enhance exercise performance and may lead to increased adiposity, abnormal endogenous tissue storage, and cardiometabolic remodeling.
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21
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Roth C, Rettenmaier L, Behringer M. High-Protein Energy-Restriction: Effects on Body Composition, Contractile Properties, Mood, and Sleep in Active Young College Students. Front Sports Act Living 2021; 3:683327. [PMID: 34212136 PMCID: PMC8239143 DOI: 10.3389/fspor.2021.683327] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/18/2021] [Indexed: 12/15/2022] Open
Abstract
Background: It is often advised to ensure a high-protein intake during energy-restricted diets. However, it is unclear whether a high-protein intake is able to maintain muscle mass and contractility in the absence of resistance training. Materials and Methods: After 1 week of body mass maintenance (45 kcal/kg), 28 male college students not performing resistance training were randomized to either the energy-restricted (ER, 30 kcal/kg, n = 14) or the eucaloric control group (CG, 45 kcal/kg, n = 14) for 6 weeks. Both groups had their protein intake matched at 2.8 g/kg fat-free-mass and continued their habitual training throughout the study. Body composition was assessed weekly using multifrequency bioelectrical impedance analysis. Contractile properties of the m. rectus femoris were examined with Tensiomyography and MyotonPRO at weeks 1, 3, and 5 along with sleep (PSQI) and mood (POMS). Results: The ER group revealed greater reductions in body mass (Δ -3.22 kg vs. Δ 1.90 kg, p < 0.001, partial η 2 = 0.360), lean body mass (Δ -1.49 kg vs. Δ 0.68 kg, p < 0.001, partial η 2 = 0.152), body cell mass (Δ -0.85 kg vs. Δ 0.59 kg, p < 0.001, partial η 2 = 0.181), intracellular water (Δ -0.58 l vs. Δ 0.55 l, p < 0.001, partial η 2 = 0.445) and body fat percentage (Δ -1.74% vs. Δ 1.22%, p < 0.001, partial η 2 = 433) compared to the CG. Contractile properties, sleep onset, sleep duration as well as depression, fatigue and hostility did not change (p > 0.05). The PSQI score (Δ -1.43 vs. Δ -0.64, p = 0.006, partial η 2 = 0.176) and vigor (Δ -2.79 vs. Δ -4.71, p = 0.040, partial η 2 = 0.116) decreased significantly in the ER group and the CG, respectively. Discussion: The present data show that a high-protein intake alone was not able to prevent lean mass loss associated with a 6-week moderate energy restriction in college students. Notably, it is unknown whether protein intake at 2.8 g/kg fat-free-mass prevented larger decreases in lean body mass. Muscle contractility was not negatively altered by this form of energy restriction. Sleep quality improved in both groups. Whether these advantages are due to the high-protein intake cannot be clarified and warrants further study. Although vigor was negatively affected in both groups, other mood parameters did not change.
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Affiliation(s)
- Christian Roth
- Department of Sports Medicine and Exercise Physiology, Institute of Sport Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Lukas Rettenmaier
- Department of Sports Medicine and Exercise Physiology, Institute of Sport Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Michael Behringer
- Department of Sports Medicine and Exercise Physiology, Institute of Sport Sciences, Goethe University Frankfurt, Frankfurt, Germany
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22
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Lee JA, Kim HY. Effect of Hanwoo Crust on the Physicochemical Properties of Emulsion-Type Sausages. Food Sci Anim Resour 2021; 41:440-451. [PMID: 34017953 PMCID: PMC8112307 DOI: 10.5851/kosfa.2021.e9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 11/10/2022] Open
Abstract
This study aimed to investigate the effects of Hanwoo crust,
inedible surface layer formed during dry aging, on the physicochemical
properties of emulsion-type sausages. Sausage samples were prepared with various
amounts of Hanwoo crust—0% (i.e., control),
1%, 2%, and 3%. The physicochemical properties studied
included the proximate composition, pH, color, water holding capacity (WHC),
cooking yield (CY), and viscosity. Texture profile analysis (TPA) and sensory
evaluation were also carried out. Protein, fat, and ash contents of the
Hanwoo crust-treated samples were found to be significantly
higher than those of the control (p<0.05). Moreover, the CIE b* value of
cooked sausage with Hanwoo crust treatments was significantly
lower than that of the control (p<0.05). The CIE L* value of uncooked and
cooked samples with 3% Hanwoo crust was significantly
lower than that of the control (p<0.05). In contrast, the CIE a* value of
uncooked and cooked samples with 3% Hanwoo crust was
significantly higher than that of the control (p<0.05). The viscosity of
the uncooked samples increased with increasing Hanwoo crust
content. Samples containing 3% Hanwoo crust exhibited
significantly higher WHC and CY than the control (p<0.05). In the TPA,
samples containing 2% and 3% Hanwoo crust showed
significantly higher hardness, gumminess, and chewiness than the control
(p<0.05). Overall, the sensory properties of Hanwoo
crust treatments were significantly better than those of the control
(p<0.05). In conclusion, adding 3% Hanwoo crust
to emulsion-type sausage leads to optimal physicochemical properties.
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Affiliation(s)
- Jeong-Ah Lee
- Department of Animal Resources Science, Kongju National University, Chungnam 32439, Korea
| | - Hack-Youn Kim
- Department of Animal Resources Science, Kongju National University, Chungnam 32439, Korea
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23
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Thomas E, Gennaro V, Battaglia G, Bellafiore M, Iovane A, Palma A, Bianco A. Upper body strength endurance evaluation: A comparison between the handgrip strength and three body weight tests. ISOKINET EXERC SCI 2021. [DOI: 10.3233/ies-202206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND: The hand-grip strength test has been widely adopted to evaluate upper limb strength. Other field based tests as push-ups and pull-ups are commonly used for the same purpose. It is however unclear if these may be used interchangeably for upper body strength evaluation. OBJECTIVE: The purpose of this investigation was to evaluate strength endurance of the upper body and understand which test could be the most appropriate for upper body evaluation. METHODS: Thirty-eight healthy young male participants were tested with three tests comprised of: 1) push-ups (PS), 2) pull-ups (PL) and 3) parallel dips (PD) performed to exhaustion. Grip strength (GS), total number of repetitions, time-to-complete the test, repetition cadence and rate of perceived exertion (RPE) were also retrieved for investigation. RESULTS: Repetitions, time-to-complete the test and repetition cadence significantly differed across the three tests (p< 0.001). No difference in the RPE was present. No correlation was present between GS and the other tests. No correlation was present between RPE and performance values and time-to-complete the tests. BMI was positively correlated to RPE in all tests. All tests strongly correlate to each other (PS vs. PL r= 0.55; PS vs. PD r= 0.64; PL vs. PD r= 0.70) and to time-to-complete the test (PS r= 0.79; PL r= 0.69; PD r= 0.66). Only the results of the PD correlate to their respective repetition cadence (r= 0.66). CONCLUSIONS: GS is not suitable to evaluate strength endurance. PS, PL and PD are all suitable to evaluate strength endurance. However, PD may be preferred to evaluate the upper body, if velocity also needs to be taken into account.
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Wilson JM, Lowery RP, Roberts MD, Sharp MH, Joy JM, Shields KA, Partl JM, Volek JS, D'Agostino DP. Effects of Ketogenic Dieting on Body Composition, Strength, Power, and Hormonal Profiles in Resistance Training Men. J Strength Cond Res 2021; 34:3463-3474. [PMID: 28399015 DOI: 10.1519/jsc.0000000000001935] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Wilson, JM, Lowery, RP, Roberts, MD, Sharp, MH, Joy, JM, Shields, KA, Partl, JM, Volek, JS, and D'Agostino, DP. Effects of ketogenic dieting on body composition, strength, power, and hormonal profiles in resistance training men. J Strength Cond Res 34(12): 3463-3474, 2020-This study investigated the impact of an isocaloric and isonitrogenous ketogenic diet (KD) versus a traditional western diet (WD) on changes in body composition, performance, blood lipids, and hormonal profiles in resistance-trained athletes. Twenty-five college-aged men were divided into a KD or traditional WD from weeks 1 to 10, with a reintroduction of carbohydrates from weeks 10 to 11, while participating in a resistance training program. Body composition, strength, power, and blood lipid profiles were determined at weeks 0, 10, and 11. A comprehensive metabolic panel and testosterone levels were also measured at weeks 0 and 11. Lean body mass (LBM) increased in both the KD and WD groups (2.4% and 4.4%, p < 0.01) at week 10. However, only the KD group showed an increase in LBM between weeks 10 and 11 (4.8%, p < 0.0001). Finally, fat mass decreased in both the KD (-2.2 ± 1.2 kg) and WD groups (-1.5 ± 1.6 kg). Strength and power increased to the same extent in the WD and KD conditions from weeks 1 to 11. No changes in any serum lipid measures occurred from weeks 1 to 10; however, a rapid reintroduction of carbohydrate from weeks 10 to 11 raised plasma triglyceride levels in the KD group. Total testosterone increased significantly from weeks 0 to 11 in the KD diet (118 ng·dl) as compared to the WD (-36 ng·dl) from pre to post while insulin did not change. The KD can be used in combination with resistance training to cause favorable changes in body composition, performance, and hormonal profiles in resistance-trained men.
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Affiliation(s)
| | - Ryan P Lowery
- Applied Science & Performance Institute, Tampa, Florida.,Department of Health and Human Performance, Concordia University Chicago, River Forest, Illinois
| | - Michael D Roberts
- Molecular and Applied Sciences Laboratory, School of Kinesiology, Auburn University, Auburn, Alabama
| | | | - Jordan M Joy
- Department of Nutrition and Food Science, Texas Woman's University, Denton, Texas
| | - Kevin A Shields
- Department of Health Sciences and Human Performance, The University of Tampa, Tampa, Florida
| | - Jeremy M Partl
- Department of Health Sciences and Human Performance, The University of Tampa, Tampa, Florida
| | - Jeff S Volek
- Department of Human Sciences, Kinesiology Program, Ohio State University, Columbus, Ohio; and
| | - Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
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Vijayam B, Malarvili MB, Md Shakhih MF, Omar N, Wahab AA. Effect of short-term ketogenic diet on end-tidal carbon dioxide. Clin Nutr ESPEN 2021; 42:124-131. [PMID: 33745565 DOI: 10.1016/j.clnesp.2021.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND & AIMS Previous studies have shown that end-tidal carbon dioxide (EtCO2) is lower with the presence of supraphysiological ketones as in the case of chronic ketogenic diet (KD) and diabetic ketoacidosis (DKA). This study aimed to determine changes in EtCO2 upon short term KD. METHODS Healthy subjects were screened not to have conditions that exerts abnormal EtCO2 nor contraindicated for KD. Subjects underwent seven days of KD while the EtCO2 and blood ketone (beta-hydroxybutyrate; β-OHB) parameters were sampled at day zero (t0) and seven (t7) of ketosis respectively. Statistically, the t-test and Pearson's coefficient were conducted to determine the changes and correlation of both parameters. RESULTS 12 subjects completed the study. The mean score ± standard deviation (SD) for EtCO2 were 35.08 ± 3.53 and 35.67 ± 3.31 mm Hg for t0 and t7 respectively. The mean score ±SD for β-OHB were 0.07 ± 0.08 and 0.87 ± 0.84 mmol/L for t0 and t7 respectively. There was no significant difference of EtCO2 between the period of study (p > 0.05) but the β-OHB increased during t7 (p < 0.05). There was also no correlation between the parameters. CONCLUSIONS These findings suggest that EtCO2 may not be utilized to determine short term nutritional ketosis.
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Affiliation(s)
- Bhuwaneswaran Vijayam
- School of Biomedical Engineering & Health Sciences, Faculty of Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor, Malaysia
| | - M B Malarvili
- School of Biomedical Engineering & Health Sciences, Faculty of Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor, Malaysia
| | - Muhammad Faiz Md Shakhih
- School of Biomedical Engineering & Health Sciences, Faculty of Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor, Malaysia
| | - Nashuha Omar
- School of Biomedical Engineering & Health Sciences, Faculty of Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor, Malaysia
| | - Asnida Abdul Wahab
- School of Biomedical Engineering & Health Sciences, Faculty of Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor, Malaysia; Medical Devices and Technology Centre (MEDITEC), Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia.
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Frączek B, Pięta A, Burda A, Mazur-Kurach P, Tyrała F. Paleolithic Diet-Effect on the Health Status and Performance of Athletes? Nutrients 2021; 13:1019. [PMID: 33801152 PMCID: PMC8004139 DOI: 10.3390/nu13031019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 01/18/2023] Open
Abstract
The aim of this meta-analysis was to review the impact of a Paleolithic diet (PD) on selected health indicators (body composition, lipid profile, blood pressure, and carbohydrate metabolism) in the short and long term of nutrition intervention in healthy and unhealthy adults. A systematic review of randomized controlled trials of 21 full-text original human studies was conducted. Both the PD and a variety of healthy diets (control diets (CDs)) caused reduction in anthropometric parameters, both in the short and long term. For many indicators, such as weight (body mass (BM)), body mass index (BMI), and waist circumference (WC), impact was stronger and especially found in the short term. All diets caused a decrease in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), albeit the impact of PD was stronger. Among long-term studies, only PD cased a decline in TC and LDL-C. Impact on blood pressure was observed mainly in the short term. PD caused a decrease in fasting plasma (fP) glucose, fP insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) and glycated hemoglobin (HbA1c) in the short run, contrary to CD. In the long term, only PD caused a decrease in fP glucose and fP insulin. Lower positive impact of PD on performance was observed in the group without exercise. Positive effects of the PD on health and the lack of experiments among professional athletes require longer-term interventions to determine the effect of the Paleo diet on athletic performance.
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Affiliation(s)
- Barbara Frączek
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Cracow, Poland; (A.P.); (P.M.-K.)
| | - Aleksandra Pięta
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Cracow, Poland; (A.P.); (P.M.-K.)
| | - Adrian Burda
- Department of Econometrics and Operational Research, Cracow University of Economics, 31-510 Cracow, Poland;
| | - Paulina Mazur-Kurach
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Cracow, Poland; (A.P.); (P.M.-K.)
| | - Florentyna Tyrała
- Department of Sports Dietetics, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland;
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Durkalec-Michalski K, Nowaczyk PM, Główka N, Ziobrowska A, Podgórski T. Is a Four-Week Ketogenic Diet an Effective Nutritional Strategy in CrossFit-Trained Female and Male Athletes? Nutrients 2021; 13:nu13030864. [PMID: 33800770 PMCID: PMC8001376 DOI: 10.3390/nu13030864] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/12/2022] Open
Abstract
This single-arm interventional study examined the effect of a 4-week ketogenic diet (KD) on aerobic capacity and discipline-specific performance in female (n = 11) and male (n = 11) CrossFit-trained athletes. The participants performed incremental cycling (ICT) and Fight Gone Bad (FGB) tests after consuming a customary diet and a KD. Pre- and post-ICT exercise blood samples were also analysed. Consuming a KD had a slight impact on aerobic capacity and no relevant effect on CrossFit-specific performance. In females, consuming a KD led to an 10.4% decrease in peak oxygen uptake during the ICT (p = 0.027) and resulted in certain alterations in haematological parameters (haemoglobin (HGB), mean corpuscular HGB, and mean corpuscular HGB concentration). Furthermore, in males, alanine aminotransferase activity increased with a simultaneous improvement in the post-ICT blood acid–base balance after consuming a KD. The pre-exercise bilirubin concentration was also elevated in the entire group after consuming a KD. In conclusion, female CrossFit-trained athletes seem to be prone to aerobic performance decrements and increased risk of developing haematological disturbances when consuming a KD. In males who consumed a KD, there was an undesirable alanine aminotransferase elevation and a small tendency towards improved acid–base status. Moreover, consuming a KD had no effect on discipline-specific performance in CrossFit-trained athletes.
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Affiliation(s)
- Krzysztof Durkalec-Michalski
- Department of Sports Dietetics, Poznan University of Physical Education, 61-871 Poznań, Poland
- Department of Human Nutrition and Dietetics, Poznan University of Life Sciences, 60-624 Poznań, Poland; (P.M.N.); (N.G.); (A.Z.)
- Correspondence:
| | - Paulina M. Nowaczyk
- Department of Human Nutrition and Dietetics, Poznan University of Life Sciences, 60-624 Poznań, Poland; (P.M.N.); (N.G.); (A.Z.)
| | - Natalia Główka
- Department of Human Nutrition and Dietetics, Poznan University of Life Sciences, 60-624 Poznań, Poland; (P.M.N.); (N.G.); (A.Z.)
| | - Anna Ziobrowska
- Department of Human Nutrition and Dietetics, Poznan University of Life Sciences, 60-624 Poznań, Poland; (P.M.N.); (N.G.); (A.Z.)
| | - Tomasz Podgórski
- Department of Physiology and Biochemistry, Poznan University of Physical Education, 61-871 Poznań, Poland;
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Ashtary-Larky D, Bagheri R, Asbaghi O, Tinsley GM, Kooti W, Abbasnezhad A, Afrisham R, Wong A. Effects of resistance training combined with a ketogenic diet on body composition: a systematic review and meta-analysis. Crit Rev Food Sci Nutr 2021; 62:5717-5732. [PMID: 33624538 DOI: 10.1080/10408398.2021.1890689] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We evaluated the effects of ketogenic diets (KDs) on body mass (BM), fat mass (FM), fat-free mass (FFM), body mass index (BMI), and body fat percentage (BFP) compared to non-KDs in individuals performing resistance training (RT). Online electronic databases including PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS, and Ovid were searched to identify initial studies until February 2021. Data were pooled using both fixed and random-effects methods and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). Out of 1372 studies, 13 randomized controlled trials (RCTs) that enrolled 244 volunteers were included. The pooled results demonstrated that KDs significantly decreased BM [(WMD = -3.67 kg; 95% CI: -4.44, -2.90, p < 0.001)], FM [(WMD = -2.21 kg; 95% CI: -3.09, -1.34, p < 0.001)], FFM [(WMD = -1.26 kg; 95% CI: -1.82, -0.70, p < 0.001)], BMI [(WMD = -1.37 kg.m-2; 95% CI: -2.14, -0.59, p = 0.022)], and BFP [(WMD = -2.27%; 95% CI: -3.63, -0.90, p = 0.001)] compared to non-KDs. We observed beneficial effects of KDs compared to non-KDs on BM and body fat (both FM and BFP) in individuals performing RT. However, adherence to KDs may have a negative effect on FFM, which is not ameliorated by the addition of RT.
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Affiliation(s)
- Damoon Ashtary-Larky
- Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Reza Bagheri
- Department of Exercise Physiology, University of Isfahan, Isfahan, Iran
| | - Omid Asbaghi
- Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Grant M Tinsley
- Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, Texas, USA
| | - Wesam Kooti
- Lung Diseases & Allergy Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Amir Abbasnezhad
- Nutritional Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Reza Afrisham
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Alexei Wong
- Department of Health and Human Performance, Marymount University, Arlington, Texas, USA
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Ma S, Yang J, Tominaga T, Liu C, Suzuki K. A Low-Carbohydrate Ketogenic Diet and Treadmill Training Enhanced Fatty Acid Oxidation Capacity but Did Not Enhance Maximal Exercise Capacity in Mice. Nutrients 2021; 13:nu13020611. [PMID: 33668504 PMCID: PMC7918427 DOI: 10.3390/nu13020611] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/04/2021] [Accepted: 02/10/2021] [Indexed: 12/28/2022] Open
Abstract
The low-carbohydrate ketogenic diet (LCKD) is a dietary approach characterized by the intake of high amounts of fat, a balanced amount of protein, and low carbohydrates, which is insufficient for metabolic demands. Previous studies have shown that an LCKD alone may contribute to fatty acid oxidation capacity, along with endurance. In the present study, we combined a 10-week LCKD with an 8-week forced treadmill running program to determine whether training in conjunction with LCKD enhanced fatty acid oxidation capacity, as well as whether the maximal exercise capacity would be affected by an LCKD or training in a mice model. We found that the lipid pool and fatty acid oxidation capacity were both enhanced following the 10-week LCKD. Further, key fatty acid oxidation related genes were upregulated. In contrast, the 8-week training regimen had no effect on fatty acid and ketone body oxidation. Key genes involved in carbohydrate utilization were downregulated in the LCKD groups. However, the improved fatty acid oxidation capacity did not translate into an enhanced maximal exercise capacity. In summary, while favoring the fatty acid oxidation system, an LCKD, alone or combined with training, had no beneficial effects in our intensive exercise-evaluation model. Therefore, an LCKD may be promising to improve endurance in low- to moderate-intensity exercise, and may not be an optimal choice for those partaking in high-intensity exercise.
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Affiliation(s)
- Sihui Ma
- Faculty of Sport Sciences, Waseda University, Tokorozawa 3591192, Japan;
- Japan Society for the Promotion of Sciences, Chiyoda-ku, Tokyo 1020083, Japan;
| | - Jiao Yang
- Graduate School of Sport Sciences, Waseda University, Tokorozawa 3591192, Japan;
- College of Food Sciences, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Food Quality and Safety, Guangzhou 510642, China
| | - Takaki Tominaga
- Japan Society for the Promotion of Sciences, Chiyoda-ku, Tokyo 1020083, Japan;
- Graduate School of Sport Sciences, Waseda University, Tokorozawa 3591192, Japan;
| | - Chunhong Liu
- College of Food Sciences, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Food Quality and Safety, Guangzhou 510642, China
- Correspondence: (C.L.); (K.S.); Tel.: +86-020-8528-3448 (C.L.); +81-04-2947-6898 (K.S.)
| | - Katsuhiko Suzuki
- Faculty of Sport Sciences, Waseda University, Tokorozawa 3591192, Japan;
- Correspondence: (C.L.); (K.S.); Tel.: +86-020-8528-3448 (C.L.); +81-04-2947-6898 (K.S.)
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Paoli A, Cenci L, Pompei P, Sahin N, Bianco A, Neri M, Caprio M, Moro T. Effects of Two Months of Very Low Carbohydrate Ketogenic Diet on Body Composition, Muscle Strength, Muscle Area, and Blood Parameters in Competitive Natural Body Builders. Nutrients 2021; 13:nu13020374. [PMID: 33530512 PMCID: PMC7911670 DOI: 10.3390/nu13020374] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/19/2022] Open
Abstract
Background: Ketogenic diet (KD) is a nutritional approach that restricts daily carbohydrates, replacing most of the reduced energy with fat, while maintaining an adequate quantity of protein. Despite the widespread use of KD in weight loss in athletes, there are still many concerns about its use in sports requiring muscle mass accrual. Thus, the present study sought to investigate the influence of a KD in competitive natural body builders. Methods: Nineteen volunteers (27.4 ± 10.5 years) were randomly assigned to ketogenic diet (KD) or to a western diet (WD). Body composition, muscle strength and basal metabolic rate were measured before and after two months of intervention. Standard blood biochemistry, testosterone, IGF-1, brain-derived neurotrophic factor (BDNF) and inflammatory cytokines (IL6, IL1β, TNFα) were also measured. Results: Body fat significantly decreased in KD (p = 0.030); whilst lean mass increased significantly only in WD (p < 0.001). Maximal strength increased similarly in both groups. KD showed a significant decrease of blood triglycerides (p < 0.001), glucose (p = 0.001), insulin (p < 0.001) and inflammatory cytokines compared to WD whilst BDNF increased in both groups with significant greater changes in KD (p < 0.001). Conclusions: KD may be used during body building preparation for health and leaning purposes but with the caution that hypertrophic muscle response could be blunted.
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Affiliation(s)
- Antonio Paoli
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
- Research Center for High Performance Sport, UCAM, Catholic University of Murcia, 30107 Murcia, Spain
| | - Lorenzo Cenci
- Brain, Mind and Computer Science Doctoral Program, University of Padua, 35131 Padua, Italy;
| | - PierLuigi Pompei
- Unit of Pharmacology, School of Pharmacy, University of Camerino, 62032 Camerino, Italy;
| | - Nese Sahin
- Faculty of Sport Science, Ankara University, 06830 Ankara, Turkey;
| | - Antonino Bianco
- Department of Psychology, Educational Science and Human Movement, Sport and Exercise Sciences Research Unit, University of Palermo, 90128 Palermo, Italy;
| | - Marco Neri
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, 00166 Rome, Italy; (M.N.); (M.C.)
| | - Massimiliano Caprio
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, 00166 Rome, Italy; (M.N.); (M.C.)
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, 00163 Rome, Italy
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
- Correspondence: ; Tel.: +39-049-827-5306
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Moore AR, Holland-Winkler AM, Ansley JK, Boone EDH, Schulte MKO. Reliability and diagnostic performance of a new blood ketone and glucose meter in humans. J Int Soc Sports Nutr 2021; 18:6. [PMID: 33413456 PMCID: PMC7791747 DOI: 10.1186/s12970-020-00404-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 12/18/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Accurate and reliable monitoring of blood ketone and glucose levels is useful for athletes adhering to a ketogenic diet who want to verify that they are in a state of ketosis and, therefore, accruing performance adaptations. However, the cost of devices and testing materials may prohibit their use. More affordable field testing systems are available, but their accuracy and reliability remain in question. The objectives of this study were to evaluate the agreement between a previously validated ketone and glucose meter (Meter 1 - Precision Xtra) and a more affordable meter that has not been validated (Meter 2 - Keto-Mojo), and also to assess the diagnostic performance of Meter 2 for identifying nutritional ketosis. METHODS Thirteen participants (7 females and 6 males; 21.6 ± 3.0 years old) visited the laboratory three times in this randomized, double-blind cross-over design study. Ketone and glucose levels were measured with Meter 1 and Meter 2 twice before and twice after ingestion of a racemic ketone, natural ketone, or maltodextrin supplement. Intraclass correlation coefficient (ICC) estimates and their 95% confidence intervals were calculated to evaluate interrater reliability for Meter 1 and Meter 2. Bland-Altman plots were constructed to visually assess the agreement between devices. Area under the ROC curve analysis was performed to evaluate the diagnostic ability of Meter 2 to detect nutritional ketosis at a threshold ketone level of 0.5 mM as identified by Meter 1. RESULTS Reliability between the meters was excellent for measuring ketones (ICC = .968; .942-.981) and good for measuring glucose (ICC = .809; .642-.893), though the Bland-Altman plot revealed substantial differences in agreement for measuring glucose. Area under the ROC curve (Area = 0.913; 0.828-0.998) was excellent for diagnosing nutritional ketosis. CONCLUSIONS Both Meter 1 and Meter 2 displayed excellent agreement between each other for ketone measurement. Meter 2 also displayed an excellent level of accuracy for diagnosing nutritional ketosis at a threshold value of 0.5 mM, making it an effective and affordable alternative to more expensive testing devices.
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Affiliation(s)
- Andrew Ray Moore
- Department of Kinesiology, Augusta University, 3109 Wrightsboro Road, Augusta, GA 30909 USA
| | | | - Jenna Kate Ansley
- Department of Kinesiology, Augusta University, 3109 Wrightsboro Road, Augusta, GA 30909 USA
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Krings BM, Waldman HS, Shepherd BD, McAllister MJ, Fountain BJ, Lamberth JG, Smith JW. The metabolic and performance effects of carbohydrate timing in resistance trained males undergoing a carbohydrate restricted diet. Appl Physiol Nutr Metab 2020; 46:626-636. [PMID: 33301383 DOI: 10.1139/apnm-2020-0830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The purpose of this investigation was to examine the importance of carbohydrate (CHO) timing while consuming a carbohydrate restricted diet (CRD) and completing a high-intensity exercise program. Eighteen males completed 6 weeks of training with the first 2 weeks serving as familiarization. During the final 4 weeks, subjects were randomized into 2 groups and completed 3 days of resistance training and 2 days of high-intensity interval training, while consuming a CRD (∼25%, ∼25%, and ∼50%, CHO, protein, and fat, respectively). The supplemented group (n = 9) ingested 30 g of CHO during exercise and 40 g of CHO immediately after each training session. The non-supplemented group (n = 9) consumed a non-caloric placebo during exercise. Pre- and post-testing measures included back squat and bench press 1-repetition maximums (1-RM), peak oxygen consumption (V̇O2peak), anaerobic power, body composition, fasted glucose, insulin, and total testosterone. Both groups significantly improved back squat and bench press 1-RM, V̇O2peak, and power output (p < 0.05), but there were no differences in blood markers or body composition. Our data suggests that CHO timing does not negatively impact training adaptations during a high-intensity exercise regimen when dietary CHO intake is restricted, but that favorable adaptations can be made while consuming a CRD. Novelty: Carbohydrate restricted dieting has no negative impact on resistance training adaptations. Short-term high-intensity interval training is effective in increasing peak oxygen consumption.
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Affiliation(s)
- Ben M Krings
- Department of Health and Human Performance, University of Wisconsin- Platteville, Platteville, Wisconsin, USA
| | - Hunter S Waldman
- Department of Kinesiology, University of North Alabama, Florence, Alabama, USA
| | - Brandon D Shepherd
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, Mississippi, USA
| | - Matthew J McAllister
- Metabolic & Applied Physiology Lab, Department of Health and Human Performance, Texas State University, San Marcos, Texas, USA
| | - Brent J Fountain
- Department of Food Science, Nutrition, and Health Promotion, Mississippi State University, Mississippi State, Mississippi, USA
| | - John G Lamberth
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, Mississippi, USA
| | - JohnEric W Smith
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, Mississippi, USA
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Locatelli CAA, Mulvihill EE. Islet Health, Hormone Secretion, and Insulin Responsivity with Low-Carbohydrate Feeding in Diabetes. Metabolites 2020; 10:E455. [PMID: 33187118 PMCID: PMC7697690 DOI: 10.3390/metabo10110455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/05/2020] [Accepted: 11/07/2020] [Indexed: 12/25/2022] Open
Abstract
Exploring new avenues to control daily fluctuations in glycemia has been a central theme for diabetes research since the Diabetes Control and Complications Trial (DCCT). Carbohydrate restriction has re-emerged as a means to control type 2 diabetes mellitus (T2DM), becoming increasingly popular and supported by national diabetes associations in Canada, Australia, the USA, and Europe. This approval comes from many positive outcomes on HbA1c in human studies; yet mechanisms underlying their success have not been fully elucidated. In this review, we discuss the preclinical and clinical studies investigating the role of carbohydrate restriction and physiological elevations in ketone bodies directly on pancreatic islet health, islet hormone secretion, and insulin sensitivity. Included studies have clearly outlined diet compositions, including a diet with 30% or less of calories from carbohydrates.
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Affiliation(s)
- Cassandra A. A. Locatelli
- Energy Substrate Laboratory, The University of Ottawa Heart Institute, 40 Ruskin Street, H-3229A, Ottawa, ON KIY 4W7, Canada;
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, 451 Smyth Rd, Ottawa, ON K1H 8L1, Canada
| | - Erin E. Mulvihill
- Energy Substrate Laboratory, The University of Ottawa Heart Institute, 40 Ruskin Street, H-3229A, Ottawa, ON KIY 4W7, Canada;
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, 451 Smyth Rd, Ottawa, ON K1H 8L1, Canada
- Montreal Diabetes Research Centre CRCHUM-Pavillion R, 900 Saint-Denis-Room R08.414, Montreal, QC H2X 0A9, Canada
- Centre for Infection, Immunity and Inflammation, The University of Ottawa, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
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Bowler AL, Polman R. Role of a Ketogenic Diet on Body Composition, Physical Health, Psychosocial Well-Being and Sports Performance in Athletes: A Scoping Review. Sports (Basel) 2020; 8:sports8100131. [PMID: 32977479 PMCID: PMC7598179 DOI: 10.3390/sports8100131] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/16/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Recently, a focus has been placed on investigating the potential benefits of adherence to a ketogenic diet in enhancing body composition, physical health, psychological well-being, and performance of athletes from various sporting disciplines. As the available research is yet to be collated and analyzed in a single review, this scoping review aims to analyze and draw conclusions from the available literature that exists on the efficacy of a ketogenic diet among athletic populations. METHODS Several primary research databases and any relevant citation lists were searched to locate appropriate studies for inclusion in this scoping review. Studies that investigated the effects of adherence to a ketogenic diet (KD), defined by a carbohydrate intake of less than 5% of total energy intake, on body composition, physical health, psychological well-being, and performance among an athletic population were included in the review. From 814 articles screened, 12 were identified as meeting the inclusion criteria and were included in the final scoping review. RESULTS Adherence to a KD has beneficial effects on body weight and fat mass. Varying effects were identified on physical health with the diet, eliciting positive effects on fat oxidation but potentially deleterious effects on stool microbiota and iron metabolism. Conflicting results were reported regarding the effects of a KD on sporting performance. Benefits were reported regarding athlete well-being following commencement of a KD, but only after week two. CONCLUSIONS The results of this scoping review demonstrate that there are both beneficial and detrimental effects associated with adherence to a KD among athletic populations. It is understood that further research is required to make any concrete recommendations regarding a KD to athletes.
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Affiliation(s)
- Amy-Lee Bowler
- Faculty of Health Sciences and Medicine, Nutrition & Dietetics, Bond University, Gold Coast QLD 4226, Australia
- Correspondence:
| | - Remco Polman
- Faculty of Health, School of Exercise & Nutrition Sciences, Queensland University of Technology, Brisbane QLD 4059, Australia;
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Changes in body composition and substrate utilization after a short-term ketogenic diet in endurance-trained males. Biol Sport 2020; 38:145-152. [PMID: 33795923 PMCID: PMC7996378 DOI: 10.5114/biolsport.2020.98448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/19/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Few studies have investigated the short-term effects of a very low carbohydrate ketogenic diet (KD) on body composition and substrate utilization in trained individuals. This study investigated effects on substrate utilization during incremental exercise, and changes in body composition, in response to seven days ad libitum consumption of a KD by athletes from endurance sports. Nine young trained males (age, 21.8 ± 1.9 y; height, 1.83 ± 0.11 m; body mass, 78.4 ± 13.8 kg; body fat, 14.9 ± 3.9%; VO2peak, 54.3 ± 5.9 mL kg-1 min-1) were assessed before (day 0; PRE) and after (day 7; POST) seven days of consuming an ad libitum KD. Following an overnight fast, body composition was measured by dual x-ray absorptiometry, and substrate utilization was measured during an incremental (3 min stages, 35 W increments) exercise test on a cycle ergometer. After KD, Wmax (PRE, 295 ± 30 W; POST, 292 ± 38 W) and VO2peak (PRE, 4.18 ± 0.33 L min-1; POST, 4.10 ± 0.43 L min-1) were unchanged, whereas body mass [-2.4 (-3.2, -1.6) kg; P < 0.001, d = 0.21], fat mass [-0.78 (-1.10, -0.46) kg; P < 0.001, d = 0.22] and fat-free mass (FFM) [-1.82 (-3.12, -0.51) kg; P = 0.013, d = 0.22] all decreased. The respiratory exchange ratio was lower, and rates of fat oxidation were higher, at POST across a range of exercise intensities. Maximal fat oxidation rate was ~1.8-fold higher after KD (PRE, 0.54 ± 0.13 g min-1; POST, 0.95 ± 0.24 g min-1; P < 0.001, d = 2.2). Short-term KD results in loss of both fat mass and FFM, increased rates of fat oxidation and a concomitant reduction in CHO utilization even at moderate-to-high intensities of exercise.
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Ari C, Murdun C, Goldhagen C, Koutnik AP, Bharwani SR, Diamond DM, Kindy M, D’Agostino DP, Kovacs Z. Exogenous Ketone Supplements Improved Motor Performance in Preclinical Rodent Models. Nutrients 2020; 12:nu12082459. [PMID: 32824223 PMCID: PMC7468837 DOI: 10.3390/nu12082459] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/05/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022] Open
Abstract
Nutritional ketosis has been proven effective for neurometabolic conditions and disorders linked to metabolic dysregulation. While inducing nutritional ketosis, ketogenic diet (KD) can improve motor performance in the context of certain disease states, but it is unknown whether exogenous ketone supplements—alternatives to KDs—may have similar effects. Therefore, we investigated the effect of ketone supplements on motor performance, using accelerating rotarod test and on postexercise blood glucose and R-beta-hydroxybutyrate (R-βHB) levels in rodent models with and without pathology. The effect of KD, butanediol (BD), ketone-ester (KE), ketone-salt (KS), and their combination (KE + KS: KEKS) or mixtures with medium chain triglyceride (MCT) (KE + MCT: KEMCT; KS + MCT: KSMCT) was tested in Sprague-Dawley (SPD) and WAG/Rij (WR) rats and in GLUT-1 Deficiency Syndrome (G1D) mice. Motor performance was enhanced by KEMCT acutely, KE and KS subchronically in SPD rats, by KEKS and KEMCT groups in WR rats, and by KE chronically in G1D mice. We demonstrated that exogenous ketone supplementation improved motor performance to various degrees in rodent models, while effectively elevated R-βHB and in some cases offsets postexercise blood glucose elevations. Our results suggest that improvement of motor performance varies depending on the strain of rodents, specific ketone formulation, age, and exposure frequency.
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Affiliation(s)
- Csilla Ari
- Department of Psychology, Behavioral Neuroscience Research Laboratory, University of South Florida, Tampa, FL 33620, USA; (S.R.B.); (D.M.D.)
- Ketone Technologies, Tampa, FL 33612, USA;
- Correspondence: or ; Tel.: +1-813-240-9925
| | - Cem Murdun
- Department of Molecular Pharmacology and Physiology, Laboratory of Metabolic Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (C.M.); (C.G.); (A.P.K.)
| | - Craig Goldhagen
- Department of Molecular Pharmacology and Physiology, Laboratory of Metabolic Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (C.M.); (C.G.); (A.P.K.)
| | - Andrew P. Koutnik
- Department of Molecular Pharmacology and Physiology, Laboratory of Metabolic Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (C.M.); (C.G.); (A.P.K.)
- Institute for Human and Machine Cognition, Ocala, FL 34471, USA
| | - Sahil R. Bharwani
- Department of Psychology, Behavioral Neuroscience Research Laboratory, University of South Florida, Tampa, FL 33620, USA; (S.R.B.); (D.M.D.)
| | - David M. Diamond
- Department of Psychology, Behavioral Neuroscience Research Laboratory, University of South Florida, Tampa, FL 33620, USA; (S.R.B.); (D.M.D.)
- Department of Molecular Pharmacology and Physiology, Laboratory of Metabolic Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (C.M.); (C.G.); (A.P.K.)
| | - Mark Kindy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL 33612, USA;
- James A. Haley VA Medical Center, Tampa, FL 33612, USA
- Shriners Hospital for Children, Tampa, FL 33612, USA
| | - Dominic P. D’Agostino
- Ketone Technologies, Tampa, FL 33612, USA;
- Department of Molecular Pharmacology and Physiology, Laboratory of Metabolic Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (C.M.); (C.G.); (A.P.K.)
- Institute for Human and Machine Cognition, Ocala, FL 34471, USA
| | - Zsolt Kovacs
- Savaria Department of Biology, ELTE Eötvös Loránd University, Savaria University Centre, Károlyi Gáspár tér 4., 9700 Szombathely, Hungary;
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Kaspar MB, Austin K, Huecker M, Sarav M. Ketogenic Diet: from the Historical Records to Use in Elite Athletes. Curr Nutr Rep 2020; 8:340-346. [PMID: 31713719 DOI: 10.1007/s13668-019-00294-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE OF REVIEW To review the available literature/evidence on low carbohydrate/high fat (LCHF) and low carbohydrate ketogenic (LCKD) diets' effects on human athletic performance and to provide a brief review of the physiology and history of energy systems of exercise. RECENT FINDINGS Multiple studies have been conducted in an attempt to answer this question, many within the last 3-5 years. Studies are heterogenous in design, intervention, and outcome measures. Current available data show that LCHF and LCKD do not significantly enhance or impair performance in endurance or strength activities. However, there is a trend towards improved body composition (greater percent lean body mass) across multiple studies. While this may not translate to enhanced performance in the primarily laboratory conditions in the reviewed studies, there could be a benefit in sports in which an athlete's strength-to-weight ratio is a significant determinant of outcome.
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Affiliation(s)
- Matthew B Kaspar
- Department of Internal Medicine, Division of Gastroenterology, Hepatology, and Nutrition, Virginia Commonwealth University Medical Center, 1200 East Broad Street, P.O. Box 980509, Richmond, VA, 23298, USA.
| | - Kerstin Austin
- Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53705, USA
| | - Martin Huecker
- Department of Emergency Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - Menaka Sarav
- Division of Nephrology and Hypertension, NorthShore University Health System, University of Chicago, Chicago, USA
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Kuchkuntla AR, Shah M, Velapati S, Gershuni VM, Rajjo T, Nanda S, Hurt RT, Mundi MS. Ketogenic Diet: an Endocrinologist Perspective. Curr Nutr Rep 2020; 8:402-410. [PMID: 31705484 DOI: 10.1007/s13668-019-00297-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Obesity and its related comorbidities make up a large part of healthcare expenditures. Despite a wide array of options for treatment of obesity, rates of sustained weight loss continue to be low, leading patients to seek alternative treatment options. Although the first medically utilized ketogenic diet was described nearly 100 years ago, it has made a resurgence as a treatment option for obesity. Despite increased popularity in the lay public and increased use of ketogenic dietary strategies for metabolic therapy, we are still beginning to unravel the metabolic impact of long-term dietary ketosis. RECENT FINDINGS There are a number of recent trials that have highlighted the short- and long-term benefits of ketogenic diet on weight, glycemic control, and other endocrine functions including reproductive hormones. This review is a summary of available data on the effectiveness and durability of the ketogenic diet when compared to conventional interventions. Ketogenic dietary strategies may play a role in short-term improvement of important metabolic parameters with potential for long-term benefit. However, response may vary due to inter-individual ability to maintain long-term carbohydrate restriction.
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Affiliation(s)
| | - Meera Shah
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Saketh Velapati
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Victoria M Gershuni
- Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Tamim Rajjo
- Department of Family Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sanjeev Nanda
- Division of General Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | - Ryan T Hurt
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.,Division of General Internal Medicine, Mayo Clinic, Rochester, MN, USA.,Division of Gastroenterology, Mayo Clinic, Rochester, MN, USA
| | - Manpreet S Mundi
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.
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Abstract
Numerous oral ketone supplements are marketed with the claim that they will rapidly induce ketosis and improve exercise performance. The purpose of this study was to assess exercise performance time and related physiological, metabolic and perceptual responses of recreational endurance runners after ingestion of a commercially available oral ketone supplement. Recreational endurance runners (n = 10; age: 20.8 ± 1.0 years; body mass: 68.9 ± 5.6 kg; height: 175.6 ± 4.9 cm) participated in a double-blind, crossover, repeated-measures study where they were randomized to 300 mg.kg-1 body weight of an oral β-hydroxybutyrate-salt + Medium Chain Triglyceride (βHB-salt+MCT) ketone supplement or a flavor matched placebo (PLA) 60 min prior to performing a 5-km running time trial (5KTT) on a treadmill. Time, HR, RPE, affect, RER, VO2, VCO2, and VE were measured during the 5-km run. The Session RPE and affect (Feeling Scale) were obtained post-5KTT. Plasma glucose, lactate and ketones were measured at baseline, 60-min post-supplement, and immediately post-5KTT. Plasma R-βHB (endogenous isomer) was elevated from baseline and throughout the entire protocol under the βHB-salt+MCT condition (p < 0.05). No significant difference (58.3 ± 100.40 s; 95% CI: -130.12 – 13.52; p = 0.100) was observed between the βHB-salt+MCT supplement (1430.0 ± 187.7 s) and the PLA (1488.3 ± 243.8 s) in time to complete the 5KTT. No other differences (p > 0.05) were noted in any of the other physiological, metabolic or perceptual measures.
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Paoli A, Mancin L, Giacona MC, Bianco A, Caprio M. Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. J Transl Med 2020; 18:104. [PMID: 32103756 PMCID: PMC7045520 DOI: 10.1186/s12967-020-02277-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/19/2020] [Indexed: 02/08/2023] Open
Abstract
Background Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women during reproductive age. It is characterised clinically by oligo-ovulation or anovulation, hyper-androgenism, and the presence of polycystic ovaries. It is associated with an increased prevalence of metabolic syndrome, cardiovascular disease and type 2 diabetes. The onset of PCOS has been associated to several hereditary and environmental factors, but insulin resistance plays a key pathogenetic role. We sought to investigate the effects of a ketogenic diet (KD) on women of childbearing age with a diagnosis of PCOS. Methods Fourteen overweight women with diagnosis of PCOS underwent to a ketogenic Mediterranean diet with phyoextracts (KEMEPHY) for 12 week. Changes in body weight, body mass index (BMI), fat body mass (FBM), lean body mass (LBM), visceral adipose tissue (VAT), insulin, glucose, HOMA-IR, total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides (TGs), total and free testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH); dehydroepiandrosterone sulfate (DHEAs), estradiol, progesterone, sex hormone binding globulin (SHBG) and Ferriman Gallwey score were evaluated. Results After 12 weeks, anthropometric and body composition measurements revealed a significant reduction of body weight (− 9.43 kg), BMI (− 3.35), FBM (8.29 kg) and VAT. There was a significant, slightly decrease of LBM. A significant decrease in glucose and insulin blood levels were observed, together with a significant improvement of HOMA-IR. A significant decrease of triglycerides, total cholesterol and LDL were observed along with a rise in HDL levels. The LH/FSH ratio, LH total and free testosterone, and DHEAS blood levels were also significantly reduced. Estradiol, progesterone and SHBG increased. The Ferriman Gallwey Score was slightly, although not significantly, reduced. Conclusions Our results suggest that a KD may be considered as a valuable non pharmacological treatment for PCOS. Longer treatment periods should be tested to verify the effect of a KD on the dermatological aspects of PCOS. Trial registration Clinicaltrial.gov, NCT04163120, registrered 10 November 2019, retrospectively registered, https://clinicaltrials.gov.
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Affiliation(s)
- Antonio Paoli
- Department of Biomedical Sciences, University of Padua, Padua, Italy. .,Research Center for High Performance Sport, UCAM, Catholic University of Murcia, Murcia, Spain.
| | - Laura Mancin
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Human Inspired Technology Research Center HIT, University of Padua, Padua, Italy
| | - Maria Cristina Giacona
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Antonino Bianco
- Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Massimiliano Caprio
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, Rome, Italy.,Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, Rome, Italy
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Abstract
The purpose of the present review is to describe how human physiology at very low carbohydrate intakes relates to the criteria for nutritional essentiality. Although we did not limit ourselves to one particular type or function of carbohydrates, we did primarily focus on glucose utilisation as that function was used to determine the recommended daily allowance. In the general population, the human body is able to endogenously synthesise carbohydrates, and does not show signs of deficiency in the absence of dietary carbohydrates. However, in certain genetic defects, such as glycogen storage disease type I, absence of dietary carbohydrates causes abnormalities that are resolved with dietary supplementation of carbohydrates. Therefore, dietary carbohydrates may be defined as conditionally essential nutrients because they are nutrients that are not required in the diet for the general population but are required for specific subpopulations. Ketosis may be considered a physiological normal state due to its occurrence in infants in addition to at very low carbohydrate intakes. Although sources of dietary carbohydrates can provide beneficial micronutrients, no signs of micronutrient deficiencies have been reported in clinical trials of low-carbohydrate ketogenic diets. Nonetheless, more research is needed on how micronutrient requirements can change depending on the dietary and metabolic context. More research is also needed on the role of dietary fibre during a low-carbohydrate ketogenic diet as the beneficial effects of dietary fibre were determined on a standard diet and several studies have shown beneficial effects of decreasing non-digestible carbohydrates.
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Waldman HS, Smith JW, Lamberth J, Fountain BJ, McAllister MJ. A 28-Day Carbohydrate-Restricted Diet Improves Markers of Cardiometabolic Health and Performance in Professional Firefighters. J Strength Cond Res 2020; 33:3284-3294. [PMID: 31469768 DOI: 10.1519/jsc.0000000000003354] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Waldman, HS, Smith, JW, Lamberth, J, Fountain, BJ, and McAllister, MJ. A 28-day carbohydrate-restricted diet improves markers of cardiometabolic health and performance in professional firefighters. J Strength Cond Res 33(12): 3284-3294, 2019-We investigated the effects of a 4-week ad-libitum, nonketogenic, carbohydrate-restricted (<25% of calories) diet (CRD) on cardiometabolic and performance markers in firefighters (FF). Subjects (n = 15) completed 9 sessions (trials 1-3 [familiarization], trials 4-6 [baseline], and trials 7-9 [post-CRD]). Following habitual western diet, anthropometric measures were assessed, glucose tolerance measured, and then completed a graded cycling test, maximal Wingate test, and conducted their FF physical performance assessment (FPPA) to measure performance while metabolic variables and perceptual responses were recorded. Subjects then adhered to a CRD for a 4-week duration and returned for repeat testing. Body fat as measured by BodPod, and 7-site skinfold thickness decreased (p < 0.01), and a decrease was observed in blood pressure (BP) (p < 0.01; ∼5 mm Hg) after CRD. There were no differences found for glucose tolerance, but an increase was found for fat oxidation rates (p < 0.01; ∼0.07 g·min) and a decrease in carbohydrate oxidation rates across a range of intensities (p < 0.01; ∼0.24 g·min). Finally, the 2.41-km run and pull-up performance during the FPPA improved (p < 0.01; ∼41 second and 3 repetitions, respectively) and with no differences observed between treatments regarding the Wingate test. To date, this is the first CRD implemented with FF and resulted in decreased fat mass (∼2.4 kg), BP, and improvements to performance on the FPPA while preserving high-intensity exercise. These data suggest that a 28-day CRD can benefit markers of health in professional FF without detriments to occupational performance.
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Affiliation(s)
- Hunter S Waldman
- Human Performance Lab, Department of Kinesiology, University of North Alabama, Florence, Alabama.,Applied Physiology Lab, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - JohnEric W Smith
- Applied Physiology Lab, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - John Lamberth
- Applied Physiology Lab, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - Brent J Fountain
- Department of Food Science, Nutrition, and Health Promotion, Mississippi State University, Starkville, Mississippi
| | - Matthew J McAllister
- Metabolic and Applied Physiology Lab, Department of Health and Human Performance, Texas State University, San Marcos, Texas
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Kang J, Ratamess NA, Faigenbaum AD, Bush JA. Ergogenic Properties of Ketogenic Diets in Normal-Weight Individuals: A Systematic Review. J Am Coll Nutr 2020; 39:665-675. [PMID: 32039654 DOI: 10.1080/07315724.2020.1725686] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ketogenic diets (KDs) have received increasing attention among athletes and physically active individuals. However, the question as to whether and how the diet could benefit this healthy cohort remains unclear.Purpose: This study was designed to systematically review the existing evidence concerning the effect of KDs on body composition, aerobic and anaerobic capacity, muscle development, and sports performance in normal-weight individuals including athletes.Methods: A systematic search of English literature was conducted through electronic databases including PubMed, EBSCOhost, and Google Scholar. Upon the use of search criteria, 23 full-text original human studies involving non-obese participants were included in this review. For more stratified and focused analysis, these articles were further categorized based on the outcomes being examined including 1) body mass (BM) and %fat, 2) substrate utilization, 3) blood substrate and hormonal responses, 4) aerobic capacity and endurance performance, and 5) strength, power, and anaerobic capacity.Results: Our review indicates that a non-calorie-restricted KD carried out for ≥3 weeks can produce a modest reduction in BM and %fat, while maintaining fat-free mass. This diet leads to augmented use of fat as fuel, but this adaptation doesn't seem to improve endurance performance. Additionally, ad libitum KDs combined with resistance training will pose no harm to developing strength and power, especially when protein intake is increased modestly.Conclusions: It appears that a non-calorie-restricted KD provides minimal ergogenic benefits in normal-weight individuals including athletes, but can be used for optimizing BM and body composition without compromising aerobic and anaerobic performance. Key teaching pointsKetogenic diets have received increasing attention among athletes and physically active individuals.It remains elusive as to whether ketogenic diets could confer ergogenic benefits for those who are normal weight but want to use the diet to improve fitness and performance.An interesting dilemma exists in that ketogenic diets can reduce body mass and %fat and increase fat oxidation, but they can also decrease glycogen stores and limit sports performance.This review concludes that a non-calorie-restricted ketogenic diet provides minimal ergogenic benefits in normal-weight individuals, but can be used to optimize body mass and composition without compromising athletic performance.This finding can be important for esthetic or weight-sensitive athletes because the diet may allow them to reach a target body mass without having to sacrifice athletic performance.The ketogenic diet-induced metabolic adaptations require a state of ketosis, and thus caution should be taken because an excessive increase in ketone bodies can be detrimental to health.
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Affiliation(s)
- Jie Kang
- Human Performance Laboratory, The College of New Jersey, Ewing, New Jersey, USA
| | - Nicholas A Ratamess
- Human Performance Laboratory, The College of New Jersey, Ewing, New Jersey, USA
| | - Avery D Faigenbaum
- Human Performance Laboratory, The College of New Jersey, Ewing, New Jersey, USA
| | - Jill A Bush
- Human Performance Laboratory, The College of New Jersey, Ewing, New Jersey, USA
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Cipryan L, Maffetone PB, Plews DJ, Laursen PB. Effects of a four-week very low-carbohydrate high-fat diet on biomarkers of inflammation: Non-randomised parallel-group study. Nutr Health 2020; 26:35-42. [PMID: 32000572 DOI: 10.1177/0260106020903206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND It is commonly assumed that increased dietary fat and/or caloric excess induces chronic inflammatory processes, since the association between obesity and chronic adipose tissue with systemic inflammation has been shown previously. As far as we know, the reported health benefits of a VLCHF or ketogenic diet have not adequately involved an evaluation of biomarkers of inflammation. AIM This study investigated the effects of a four-week very low-carbohydrate high-fat (VLCHF) diet in healthy young individuals on biomarkers of inflammation. METHODS Eighteen moderately trained males (age 23.8 ± 2.1 years) were assigned to two groups. One group switched to a non-standardised VLCHF diet for four weeks, while the second group remained consuming their normal habitual diet (HD). Biomarkers of inflammation (adiponectin, leptin, resistin and interleukin-6) and substrate metabolism (fasting glucose and triacylglyceride concentrations) were analysed from blood at baseline and after four weeks. RESULTS There was moderate evidence for substantial changes in leptin serum concentrations in the VLCHF group, with small to large decreases compared to the HD group after four weeks (effect size = 0.78, 95% CI 0.42, 0.93, p = 0.008; Bayes Factor10 = 5.70). No substantial between-group change differences over time were found across any other biomarkers. CONCLUSIONS A four-week period of consuming a VLCHF diet in healthy young men was not associated with any considerable changes in markers of inflammation but showed evidence for lowered serum leptin concentrations relative to the HD group.
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Affiliation(s)
- Lukas Cipryan
- Department of Human Movement Studies and Human Motion Diagnostic Centre, Ostrava University, Czech Republic
| | | | - Daniel J Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, New Zealand
| | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, New Zealand
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46
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Buechert M, Lange T, Deibert P, Urbain P. In Vivo Fat Quantification: Monitoring Effects of a 6-Week Non-Energy-Restricted Ketogenic Diet in Healthy Adults Using MRI, ADP and BIA. Nutrients 2020; 12:nu12010244. [PMID: 31963475 PMCID: PMC7019649 DOI: 10.3390/nu12010244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/23/2019] [Accepted: 01/08/2020] [Indexed: 11/20/2022] Open
Abstract
The ketogenic diet (KD) is a very low-carbohydrate, high-fat, and adequate-protein diet that induces many metabolic adaptations when calorie intake is not limited. Its therapeutic use in a range of diseases including cancer is currently being investigated. Our objective was to firstly assess the impact of a 6-week non-energy-restricted KD on the abdominal fat distribution and the hepatic fat composition in healthy adults. Body fat distribution and composition were measured by comparing magnetic resonance imaging (MRI) and spectroscopy (MRS) results with air displacement plethysmography (ADP) and bioelectrical impedance analysis (BIA) measurements. A total of 12 subjects from the KetoPerformance study were recruited for this ancillary study. Body mass index (BMI), total mass, total fat mass, total subcutaneous mass, and subcutaneous fat mass decreased significantly. None of the MRS parameters showed a significant change during the study. Even though the average change in body weight was >2kg, no significant changes in intrahepatic lipid (IHL) content could be observed. Total fat mass and total fat-free mass derived from MRI has a strong correlation with the corresponding values derived from BIA and ADP data. BMI and the absolute fat parameter of all three modalities decreased, but there were no or only minor changes regarding the fat-free parameter. Magnetic resonance imaging provides body composition information on abdominal fat distribution changes during a ketogenic diet. This information is complementary to anthropomorphic and laboratory measures and is more detailed than the information provided by ADP and BIA measures. It was shown that there was no significant change in internal fat distribution, but there was a decrease in subcutaneous fat.
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Affiliation(s)
- Martin Buechert
- Department of Radiology, Medical Physics, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany;
- Correspondence:
| | - Thomas Lange
- Department of Radiology, Medical Physics, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany;
| | - Peter Deibert
- Institute for Exercise—und Occupational Medicine, Center for Medicine, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany;
| | - Paul Urbain
- Department of Medicine I, Section of Clinical Nutrition and Dietetics, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany;
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47
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Prins PJ, Noakes TD, Welton GL, Haley SJ, Esbenshade NJ, Atwell AD, Scott KE, Abraham J, Raabe AS, Buxton JD, Ault DL. High Rates of Fat Oxidation Induced by a Low-Carbohydrate, High-Fat Diet, Do Not Impair 5-km Running Performance in Competitive Recreational Athletes. J Sports Sci Med 2019; 18:738-750. [PMID: 31827359 PMCID: PMC6873122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
A common belief is that high intensity exercise (>60%VO2max) is best sustained by high rates of carbohydrate oxidation. The belief is based, in part, on an idea developed by Krogh and Lindhard in 1920. In the 100 years since, few studies have tested its validity. We tested the null hypothesis that performance in competitive recreational athletes exercising at >80% VO2max, during simulated 5-km running time trials (5KTT) would be impaired during a 6-week period of adaption to a low-carbohydrate, high-fat (LCHF) diet, compared to their performances when they ate a diet higher in carbohydrate and lower in fat (HCLF). Seven male athletes (age 35.6 ± 8.4 years, height 178.7 ± 4.1 cm, weight 68.6 ± 1.6 kg) completed two maximal exercise (VO2max) tests (Day 1 and 39) and four 5KTT (Day 4, 14, 28, and 42) in a fasted state during two 6-week periods when they ate either a HCLF or a LCHF diet, in a randomized counterbalanced, crossover design. Exercise performance during the VO2max tests was unchanged on either diet (p = 0.251). Performance in the initial 5KTT was significantly slower on the LCHF diet (p = 0.011). There were no diet-related performance differences in the remaining three 5KTT (p > 0.22). Subjects exercised at ~82%VO2max. Carbohydrate oxidation provided 94% of energy on the HCLF diet, but only 65% on the LCHF diet. 5KTT performance at ~82%VO2max was independent of the runners' habitual diet. The HCLF diet offered no advantage over a diet with a high-fat content. Since these athletes run faster than 88% of recreational distance runners in the United States (U.S.), this finding may have wide general application.
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Affiliation(s)
- Philip J Prins
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | | | - Gary L Welton
- Department of Psychology, Grove City College, Grove City, Pennsylvania, USA
| | - Sarah J Haley
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | - Noah J Esbenshade
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | - Adam D Atwell
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | - Katie E Scott
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | - Jacqueline Abraham
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | - Amy S Raabe
- Department of Human Ecology, Youngstown State University, Youngstown, Ohio, USA
| | - Jeffrey D Buxton
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
| | - Dana L Ault
- Department of Exercise Science, Grove City College, Grove City, Pennsylvania, USA
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48
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McSwiney FT, Doyle L, Plews DJ, Zinn C. Impact Of Ketogenic Diet On Athletes: Current Insights. Open Access J Sports Med 2019; 10:171-183. [PMID: 31814784 PMCID: PMC6863116 DOI: 10.2147/oajsm.s180409] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/04/2019] [Indexed: 02/05/2023] Open
Abstract
The impact of a ketogenic diet (KD) (<50 g/d carbohydrate, >75% fat) on athletic performance has sparked much interest and self-experimentation in the past 3-4 years. Evidence shows 3-4-week adaptations to a KD in endurance-trained athletes were associated with maintenance of moderate (46-63% VO2max) and vigorous intensity (64-90% VO2max) endurance exercise, while at intensities >70% VO2max, increases in fat oxidation were associated with decreased economy (increased oxygen consumption), and in some cases, increased ratings of perceived exertion and heart rate. Two investigations in recreationally active endurance athletes noted no vigorous intensity exercise decrement following 3- and 12-week adaptations. Moderate (70-85% one repetition maximum) and near-maximal to maximal intensity (>85% 1RM) strength performance experienced no decrement following a 3-12-week KD adaptation. Beneficial effects were noted for 2000 m sprint and critical power test completed for short duration at vigorous intensity, while two additional tests noted no decrement. For sprint, near-maximal exercise (>91% VO2max), benefit of the KD was observed for six-second sprint, while no decrement in performance was noted for two additional maximal tests. When protein is equated (grams per kilogram), one investigation noted no decrement in muscle hypertrophy, while one noted a decrement. One investigation with matched protein noted the KD group lost more body fat. In conclusion, moderate-to-vigorous intensity exercise experiences no decrement following adaptation to a KD. Decreases in exercise economy are observed >70% VO2max in trained endurance athletes which may negate performance within field settings. Beneficial effects of the KD during short duration vigorous, and sprint bouts of exercises are often confounded by greater weight loss in the KD group. With more athletes pursuing carbohydrate-restricted diets (moderate and strict (KD)) for their proposed health benefits, more work is needed in the area to address both performance and health outcomes.
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Affiliation(s)
- Fionn T McSwiney
- School of Health and Human Performance, Dublin City University, Dublin, Ireland.,Setanta College, Thurlus, Tipperary, Ireland
| | - Lorna Doyle
- Department of Sport and Exercise Science, Waterford Institute of Technology, Waterford, Ireland
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Caryn Zinn
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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49
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Harvey KL, Holcomb LE, Kolwicz SC. Ketogenic Diets and Exercise Performance. Nutrients 2019; 11:nu11102296. [PMID: 31561520 PMCID: PMC6835497 DOI: 10.3390/nu11102296] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 02/07/2023] Open
Abstract
The ketogenic diet (KD) has gained a resurgence in popularity due to its purported reputation for fighting obesity. The KD has also acquired attention as an alternative and/or supplemental method for producing energy in the form of ketone bodies. Recent scientific evidence highlights the KD as a promising strategy to treat obesity, diabetes, and cardiac dysfunction. In addition, studies support ketone body supplements as a potential method to induce ketosis and supply sustainable fuel sources to promote exercise performance. Despite the acceptance in the mainstream media, the KD remains controversial in the medical and scientific communities. Research suggests that the KD or ketone body supplementation may result in unexpected side effects, including altered blood lipid profiles, abnormal glucose homeostasis, increased adiposity, fatigue, and gastrointestinal distress. The purpose of this review article is to provide an overview of ketone body metabolism and a background on the KD and ketone body supplements in the context of obesity and exercise performance. The effectiveness of these dietary or supplementation strategies as a therapy for weight loss or as an ergogenic aid will be discussed. In addition, the recent evidence that indicates ketone body metabolism is a potential target for cardiac dysfunction will be reviewed.
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Affiliation(s)
- Kristin L Harvey
- Heart and Muscle Metabolism Laboratory, Health and Exercise Physiology, Ursinus College, Collegeville, PA 19426, USA.
| | - Lola E Holcomb
- Heart and Muscle Metabolism Laboratory, Health and Exercise Physiology, Ursinus College, Collegeville, PA 19426, USA.
| | - Stephen C Kolwicz
- Heart and Muscle Metabolism Laboratory, Health and Exercise Physiology, Ursinus College, Collegeville, PA 19426, USA.
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50
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Sherrier M, Li H. The impact of keto-adaptation on exercise performance and the role of metabolic-regulating cytokines. Am J Clin Nutr 2019; 110:562-573. [PMID: 31347659 DOI: 10.1093/ajcn/nqz145] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 06/19/2019] [Indexed: 12/20/2022] Open
Abstract
The ketogenic diet (KD) is a normocaloric diet composed of high-fat, low-carbohydrate, and adequate protein that induces fasting-like effects and results in the production of ketone bodies. Initially used widely for children with refractory epilepsy, the KD gained popularity due to its beneficial effects on weight loss, diabetes, and cancer. In recent years, there has been a resurgence in interest surrounding the KD and exercise performance. This review provides new insights into the adaptation period necessary for enhancement in skeletal muscle fat and ketone oxidation after sustained nutritional ketosis. In addition, this review highlights metabolically active growth factors and cytokines, which may function as important regulators of keto-adaptation in the setting of exercise and the KD.
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Affiliation(s)
- Matthew Sherrier
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Hongshuai Li
- Musculoskeletal Growth and Regeneration Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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