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Moitzi AM, Krššák M, Klepochova R, Triska C, Csapo R, König D. Effects of a 10-Week Exercise and Nutritional Intervention with Variable Dietary Carbohydrates and Glycaemic Indices on Substrate Metabolism, Glycogen Storage, and Endurance Performance in Men: A Randomized Controlled Trial. SPORTS MEDICINE - OPEN 2024; 10:36. [PMID: 38600291 PMCID: PMC11006643 DOI: 10.1186/s40798-024-00705-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/24/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND Daily nutrition plays an important role in supporting training adaptions and endurance performance. The objective of this 10-week study was to investigate the consequences of varying carbohydrate consumption and the glycaemic index (GI) together with an endurance training regimen on substrate oxidation, muscle energy storage and endurance performance under free-living conditions. Sixty-five moderately trained healthy men (29 ± 4 years; VO2 peak 55 ± 8 mL min-1 kg-1) were randomized to one of three different nutritional regimes (LOW-GI: 50-60% CHO with ≥ 65% of these CHO with GI < 50 per day, n = 24; HIGH-GI: 50-60% CHO with ≥ 65% CHO with GI > 70 per day, n = 20; LCHF: ≤ 50 g CHO daily, n = 21). Metabolic alterations and performance were assessed at baseline (T0) and after 10 weeks (T10) during a graded exercise treadmill test. Additionally, a 5 km time trial on a 400-m outdoor track was performed and muscle glycogen was measured by magnet resonance spectroscopy. RESULTS Total fat oxidation expressed as area under the curve (AUC) during the graded exercise test increased in LCHF (1.3 ± 2.4 g min-1 × km h-1, p < 0.001), remained unchanged in LOW-GI (p > 0.05) and decreased in HIGH-GI (- 1.7 ± 1.5 g min-1 × km h-1, p < 0.001). After the intervention, LOW-GI (- 0.4 ± 0.5 mmol L-1 × km h-1, p < 0.001) and LCHF (- 0.8 ± 0.7 mmol L-1 × km h-1, p < 0.001) showed significantly lower AUC of blood lactate concentrations. Peak running speed increased in LOW-GI (T0: 4.3 ± 0.4 vs. T10: 4.5 ± 0.3 m s-1, p < 0.001) and HIGH-GI (T0: 4.4 ± 0.5 vs. T10: 4.6 ± 0.4 m s-1), while no improvement was observed in LCHF. Yet, time trial performance improved significantly in all groups. Muscle glycogen content increased for participants in HIGH-GI (T0: 97.3 ± 18.5 vs. T10: 144.5 ± 39.8 mmol L wet-tissue-1, p = 0.027) and remained unchanged in the LOW-GI and the LCHF group. At the last examination, muscle glycogen concentration was significantly higher in LOW-GI compared to LCHF (p = 0.014). CONCLUSION Changes in fat oxidation were only present in LCHF, however, lower lactate concentrations in LOW-GI resulted in changes indicating an improved substrate metabolism. Compared to a LCHF diet, changes in peak running speed, and muscle glycogen stores were superior in LOW- and HIGH-GI diets. The low GI diet seems to have an influence on substrate metabolism without compromising performance at higher intensities, suggesting that a high-carbohydrate diet with a low GI is a viable alternative to a LCHF or a high GI diet. TRIAL REGISTRATION Clinical Trials, NCT05241730. https://clinicaltrials.gov/study/NCT05241730 . Registered 25 January 2021.
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Affiliation(s)
- Anna Maria Moitzi
- Division of Nutrition, Exercise and Health, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria.
- Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences, University of Vienna, Vienna, Austria.
- Division of Nurtition, Exercise and Health, Department of Sport and Human Movement Science, University of Vienna, Vienna, Austria.
| | - Martin Krššák
- Department of Biomedical Imaging and Image Guided Therapy, High Field MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Radka Klepochova
- Department of Biomedical Imaging and Image Guided Therapy, High Field MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Christoph Triska
- Leistungssport Austria, High Performance Centre, Brunn am Gebirge, Lower Austria, Austria
- Division of Training Science, Department of Sport and Human Movement Science, University of Vienna, Vienna, Austria
| | - Robert Csapo
- Division of Training Science, Department of Sport and Human Movement Science, University of Vienna, Vienna, Austria
| | - Daniel König
- Division of Nutrition, Exercise and Health, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria
- Division of Nurtition, Exercise and Health, Department of Sport and Human Movement Science, University of Vienna, Vienna, Austria
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Smee SN, Johnson R, Rush A, Davey RJ. A very low carbohydrate diet for minimising blood glucose excursions during ultra-endurance open-water swimming in type 1 diabetes: a case report. Appl Physiol Nutr Metab 2024; 49:554-559. [PMID: 38109711 DOI: 10.1139/apnm-2023-0266] [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] [Indexed: 12/20/2023]
Abstract
Carbohydrate-restricted diets are used by people with type 1 diabetes (T1D) to help manage their condition. However, the impact of this strategy on blood glucose responses to exercise is unknown. This study describes the nutritional strategies of an athlete with T1D, who follows a very low carbohydrate diet to manage her condition during an ultra-endurance open-water swimming event. The athlete completed the 19.7 km distance in 6 h 43 min. She experienced minimal disruptions to glycaemia, reduced need for supplemental carbohydrate, and no episodes of symptomatic hypoglycaemia. This case report will hopefully encourage further experimental studies that inform and expand current clinical practice guidelines.
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Affiliation(s)
- Shania N Smee
- Curtin School of Allied Health, Curtin University, Whadjuk Noongar Country, Perth, Western Australia, Australia
- Rio Tinto Children's Diabetes Centre, Telethon Kids Institute, Whadjuk Noongar Country, Perth, Western Australia, Australia
| | - Rebecca Johnson
- Type 1 Diabetes Family Centre, Whadjuk Noongar Country, Perth, Western Australia, Australia
| | - Amy Rush
- Type 1 Diabetes Family Centre, Whadjuk Noongar Country, Perth, Western Australia, Australia
| | - Raymond J Davey
- Curtin School of Allied Health, Curtin University, Whadjuk Noongar Country, Perth, Western Australia, Australia
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Kruszewski M, Kruszewski A, Tabęcki R, Kuźmicki S, Stec K, Ambroży T, Aksenov MO, Merchelski M, Danielik T. Effectiveness of high-fat and high-carbohydrate diets on body composition and maximal strength after 15 weeks of resistance training. Adv Med Sci 2024; 69:139-146. [PMID: 38428587 DOI: 10.1016/j.advms.2024.02.008] [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: 06/15/2023] [Revised: 12/09/2023] [Accepted: 02/25/2024] [Indexed: 03/03/2024]
Abstract
PURPOSE The aim of this study was to compare High Carbohydrates Low Fat (HCLF) and Low Carbohydrate High Fat (LCHF) diets in terms of changes in body composition and maximal strength. PATIENTS/METHODS The study involved 48 men aged 25 ± 2.5, divided into two groups, one of which (n = 23) was following the LCHF diet and the other (n = 25) the HCLF diet. Both groups performed the same resistance training protocol for 15 weeks. Maximal strength in squat, bench press and deadlift was assessed pre- and post-intervention. Measurements of selected body circumferences and tissue parameters were made using the multifunctional, multi-frequency, direct bioelectric impedance InBody 770 analyzer from InBody Co., Ltd (Cerritos, California, USA). The team with the necessary qualifications and experience in research performed all the measurements and maintained participants' oversight throughout the entire length of the study. RESULTS Both nutritional approaches were effective in terms of reducing body fat mass. The HCLF group achieved greater skeletal muscle hypertrophy. Significant decreases in body circumferences, especially in the abdominal area, were observed for both dietary approaches. Maximal strength significantly increased in the HCLF group and decreased in the LCHF group. CONCLUSION Holistic analysis of the results led to the conclusion that both dietary approaches may elicit positive adaptations in body composition. The two approaches constitute useful alternatives for both recreational exercisers and physique athletes with body composition goals.
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Affiliation(s)
- Marek Kruszewski
- Department of Physical Education, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland.
| | - Artur Kruszewski
- Department of Physical Education, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
| | - Rafał Tabęcki
- Department of Physical Education, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
| | - Stanisław Kuźmicki
- Department of Physical Education, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
| | - Krzysztof Stec
- Department of Health Sciences, Jan Długosz University in Częstochowa, Częstochowa, Poland
| | - Tadeusz Ambroży
- Institute of Sport Sciences, University of Physical Education in Kraków, Cracow, Poland
| | - Maksim Olegovich Aksenov
- Plekhanov Russian University of Economics, Academic Department of Physical Education, Moscow, Russia; Banzarov Buryat State University, Department of Physical Education Theory, Faculty of Physical Training, Sport and Tourism, Ulan-Ude, Russia
| | - Maciej Merchelski
- Department of Physical Education, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
| | - Tomasz Danielik
- Department of Physical Education, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
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Berger NJA, Best R, Best AW, Lane AM, Millet GY, Barwood M, Marcora S, Wilson P, Bearden S. Limits of Ultra: Towards an Interdisciplinary Understanding of Ultra-Endurance Running Performance. Sports Med 2024; 54:73-93. [PMID: 37751076 DOI: 10.1007/s40279-023-01936-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2023] [Indexed: 09/27/2023]
Abstract
Ultra-endurance running (UER) poses extreme mental and physical challenges that present many barriers to completion, let alone performance. Despite these challenges, participation in UER events continues to increase. With the relative paucity of research into UER training and racing compared with traditional endurance running distance (e.g., marathon), it follows that there are sizable improvements still to be made in UER if the limitations of the sport are sufficiently understood. The purpose of this review is to summarise our current understanding of the major limitations in UER. We begin with an evolutionary perspective that provides the critical background for understanding how our capacities, abilities and limitations have come to be. Although we show that humans display evolutionary adaptations that may bestow an advantage for covering large distances on a daily basis, these often far exceed the levels of our ancestors, which exposes relative limitations. From that framework, we explore the physiological and psychological systems required for running UER events. In each system, the factors that limit performance are highlighted and some guidance for practitioners and future research are shared. Examined systems include thermoregulation, oxygen delivery and utilisation, running economy and biomechanics, fatigue, the digestive system, nutritional and psychological strategies. We show that minimising the cost of running, damage to lower limb tissue and muscle fatigability may become crucial in UER events. Maintaining a sustainable core body temperature is critical to performance, and an even pacing strategy, strategic heat acclimation and individually calculated hydration all contribute to sustained performance. Gastrointestinal issues affect almost every UER participant and can be due to a variety of factors. We present nutritional strategies for different event lengths and types, such as personalised and evidence-based approaches for varying types of carbohydrate, protein and fat intake in fluid or solid form, and how to avoid flavour fatigue. Psychology plays a vital role in UER performance, and we highlight the need to be able to cope with complex situations, and that specific long and short-term goal setting improves performance. Fatigue in UER is multi-factorial, both physical and mental, and the perceived effort or level of fatigue have a major impact on the ability to continue at a given pace. Understanding the complex interplay of these limitations will help prepare UER competitors for the different scenarios they are likely to face. Therefore, this review takes an interdisciplinary approach to synthesising and illuminating limitations in UER performance to assist practitioners and scientists in making informed decisions in practice and applicable research.
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Affiliation(s)
- Nicolas J A Berger
- School of Health and Life Sciences, Teesside University, Middlesbrough, UK.
| | - Russ Best
- Centre for Sport Science and Human Performance, Wintec, Hamilton, New Zealand
| | - Andrew W Best
- Department of Biology, Massachusetts College of Liberal Arts, North Adams, MA, USA
| | - Andrew M Lane
- Faculty of Education Health and Wellbeing, University of Wolverhampton, Walsall, UK
| | - Guillaume Y Millet
- Univ Lyon, UJM Saint-Etienne, Inter-University Laboratory of Human Movement Biology, Saint Etienne, France
- Institut Universitaire de France (IUF), Paris, France
| | - Martin Barwood
- Department of Sport, Health and Nutrition, Leeds Trinity University Horsforth, Leeds, UK
| | - Samuele Marcora
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Patrick Wilson
- Department of Human Movement Sciences, Old Dominion University, Norfolk, VA, USA
| | - Shawn Bearden
- Department of Biological Sciences, Idaho State University, Pocatello, ID, USA
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Best R, Williams JM, Pearce J. The Physiological Requirements of and Nutritional Recommendations for Equestrian Riders. Nutrients 2023; 15:4977. [PMID: 38068833 PMCID: PMC10708571 DOI: 10.3390/nu15234977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Equestrian sport is under-researched within the sport science literature, creating a possible knowledge vacuum for athletes and support personnel wishing to train and perform in an evidence-based manner. This review aims to synthesise available evidence from equitation, sport, and veterinary sciences to describe the pertinent rider physiology of equestrian disciplines. Estimates of energy expenditure and the contribution of underpinning energy systems to equestrian performance are used to provide nutrition and hydration recommendations for competition and training in equestrian disciplines. Relative energy deficiency and disordered eating are also considered. The practical challenges of the equestrian environment, including competitive, personal, and professional factors, injury and concussion, and female participation, are discussed to better highlight novelty within equestrian disciplines compared to more commonly studied sports. The evidence and recommendations are supported by example scenarios, and future research directions are outlined.
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Affiliation(s)
- Russ Best
- Centre for Sport Science & Human Performance, Waikato Institute of Technology, Te Pūkenga, Hamilton 3200, New Zealand
| | - Jane M. Williams
- Department of Animal Science, Hartpury University, Hartpury Gl19 3BE, UK;
| | - Jeni Pearce
- High Performance Sport New Zealand, Auckland 0632, New Zealand;
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Moitzi AM, König D. Longer-Term Effects of the Glycaemic Index on Substrate Metabolism and Performance in Endurance Athletes. Nutrients 2023; 15:3028. [PMID: 37447354 DOI: 10.3390/nu15133028] [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: 06/13/2023] [Revised: 06/29/2023] [Accepted: 07/02/2023] [Indexed: 07/15/2023] Open
Abstract
Nutrition has a decisive influence on athletic performance. However, it is not only the nutrient intake during exercise that is important, but the daily diet must also be adapted to the requirements of physical activity in order to optimally promote training adaptations. The goal of prolonged endurance training is to enhance fat oxidation, to maintain aerobic performance at a higher intensity while sparing limited carbohydrate stores. The targeted modification of macronutrient intake is a common method of influencing substrate metabolism, fuel selection, and performance. However, it is not well established whether the glycaemic index of carbohydrates in our daily diet can improve endurance performance by influencing carbohydrate or fat oxidation during training. Therefore, the aim of the following review is to elucidate the possible influence of the glycaemic index on substrate utilization during exercise and to clarify whether the consumption of a long-term high-carbohydrate diet with different glycaemic indices may have an influence on substrate metabolism and endurance performance.
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Affiliation(s)
- Anna Maria Moitzi
- Division for Nutrition, Exercise and Health, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
- Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences, University of Vienna, 1090 Vienna, Austria
| | - Daniel König
- Division for Nutrition, Exercise and Health, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
- Division for Nutrition, Exercise and Health, Department of Sport Science, Centre for Sports Science and University Sports, University of Vienna, 1150 Vienna, Austria
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Ilhan A, Muniroglu S, Rakıcıoğlu N. Effect of body composition on the athletic performance of soccer referees. J Nutr Sci 2023; 12:e66. [PMID: 37396457 PMCID: PMC10307644 DOI: 10.1017/jns.2023.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Nutrition plays an important role in improving sports performance. The present study aimed at nutritional assessment and examined the relationship between athletic performance and body composition in soccer referees at different levels. The study participants were 120 male soccer referees. 5, 10 and 30 metres (m) sprint tests to measure speed and cooper test for physical fitness were applied in the referees. Participants were divided into two groups as city and class soccer referee. The anthropometric measurements, excluding fat mass (FM) (%), were higher in class referees. Fat mass (%) differences (14⋅1 ± 4⋅28 v. 12⋅3 ± 4⋅41) were statistically significant (P < 0⋅05). Daily energy and nutrient intakes were similar. The inadequacy percentages of energy, vitamin A and calcium were the highest (29⋅2, 30⋅0 and 34⋅2 %, respectively). It was found that a negative significant correlation between FM% and cooper test score (P < 0⋅01; r = -0⋅35), a positive significant correlation between FM% and 5, 10 and 30 m sprint test scores (P < 0⋅01, r = 0⋅38; P < 0⋅01, r = 0⋅38 and P < 0⋅01, r = 0⋅48, respectively). Similarly, there was a negative significant correlation between waist circumference (WC) and cooper test score (P < 0⋅01; r = -0⋅31), a positive significant correlation between WC and 5, 10 and 30 m sprint test scores (P < 0⋅01, r = 0⋅33; P < 0⋅01, r = 0⋅40; P < 0⋅01, r = 0⋅33, respectively). Nutritional recommendations for soccer referees should be made specific to the individual, considering body composition, training intensity and match frequency by a dietician.
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Affiliation(s)
- Azad Ilhan
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Hacettepe University, Sıhhıye 06100, Ankara, Turkey
| | - Surhat Muniroglu
- Faculty of Sports Sciences, Department of Coaching Education, Ankara University, Ankara 06830, Turkey
| | - Neslişah Rakıcıoğlu
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Hacettepe University, Sıhhıye 06100, Ankara, Turkey
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Moss K, Kreutzer A, Graybeal AJ, Zhang Y, Braun-Trocchio R, Porter RR, Shah M. Nutrient Adequacy in Endurance Athletes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:5469. [PMID: 37107749 PMCID: PMC10138386 DOI: 10.3390/ijerph20085469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/21/2023] [Accepted: 04/04/2023] [Indexed: 05/11/2023]
Abstract
Proper nutrition is critical for optimal performance in endurance athletes. However, it is unclear if endurance athletes are meeting all their energy and nutrient needs. We examined if endurance athletes are meeting their nutritional requirements and if this differed by sex. Ninety-five endurance athletes (n = 95; 50.5% men; 34.9 ± 12.9 y) participated in the study. Dietary intake was evaluated using the 24 h dietary recall method. Energy and nutrient intakes were calculated using the ESHA Food Processor Diet Analysis Software and compared against reference nutrient intakes. Endurance athletes did not consume the recommended amount of energy (76.8% of athletes), carbohydrates (95.8%), linoleic acid (75.8%), α-linolenic acid (ALA) (77.9%), eicosatetraenoic and docosahexaenoic acid (96.8%), dietary fiber (49.5%), vitamins D (93.7%), E (71.6%), and K (54.7%), folate (54.7%), pantothenic acid (70.5%), biotin (83.2%), manganese (58.9%), magnesium (56.8%), chromium (91.6%), molybdenum (93.7%), choline (85.3%), and potassium (56.8%), and consumed too much saturated fat (50.5%) and sodium (94.7%) than recommended. Fisher's Exact test showed that the requirements for dietary fiber (70.8% vs. 27.7%), ALA (87.5% vs. 68.1%), and total water (70.8% vs. 44.7%) were not met by more men versus women (p < 0.05). The needs for protein (70.2% vs. 25%) and vitamin B12 (46.8% vs. 22.9%) were not met by more women compared to men (p < 0.05). These findings need to be confirmed by a larger study.
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Affiliation(s)
- Kamiah Moss
- Department of Kinesiology, Texas Christian University, Fort Worth, TX 76129, USA
- Physical Medicine and Rehabilitation, Baylor Institute for Rehabilitation, Dallas, TX 75246, USA
| | - Andreas Kreutzer
- Department of Kinesiology, Texas Christian University, Fort Worth, TX 76129, USA
- School of Health Promotion & Kinesiology, Texas Woman’s University, Denton, TX 76204, USA
| | - Austin J. Graybeal
- School of Kinesiology & Nutrition, College of Education and Human Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Yan Zhang
- Harris College of Nursing & Health Sciences, Texas Christian University, Fort Worth, TX 76129, USA
| | - Robyn Braun-Trocchio
- Department of Kinesiology, Texas Christian University, Fort Worth, TX 76129, USA
| | - Ryan R. Porter
- Department of Kinesiology, Texas Christian University, Fort Worth, TX 76129, USA
| | - Meena Shah
- Department of Kinesiology, Texas Christian University, Fort Worth, TX 76129, USA
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Noakes TD, Prins PJ, Volek JS, D’Agostino DP, Koutnik AP. Low carbohydrate high fat ketogenic diets on the exercise crossover point and glucose homeostasis. Front Physiol 2023; 14:1150265. [PMID: 37057184 PMCID: PMC10086139 DOI: 10.3389/fphys.2023.1150265] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
In exercise science, the crossover effect denotes that fat oxidation is the primary fuel at rest and during low-intensity exercise with a shift towards an increased reliance on carbohydrate oxidation at moderate to high exercise intensities. This model makes four predictions: First, >50% of energy comes from carbohydrate oxidation at ≥60% of maximum oxygen consumption (VO2max), termed the crossover point. Second, each individual has a maximum fat oxidation capacity (FATMAX) at an exercise intensity lower than the crossover point. FATMAX values are typically 0.3-0.6 g/min. Third, fat oxidation is minimized during exercise ≥85%VO2max, making carbohydrates the predominant energetic substrate during high-intensity exercise, especially at >85%VO2max. Fourth, high-carbohydrate low-fat (HCLF) diets will produce superior exercise performances via maximizing pre-exercise storage of this predominant exercise substrate. In a series of recent publications evaluating the metabolic and performance effects of low-carbohydrate high-fat (LCHF/ketogenic) diet adaptations during exercise of different intensities, we provide findings that challenge this model and these four predictions. First, we show that adaptation to the LCHF diet shifts the crossover point to a higher %VO2max (>80%VO2max) than previously reported. Second, substantially higher FATMAX values (>1.5 g/min) can be measured in athletes adapted to the LCHF diet. Third, endurance athletes exercising at >85%VO2max, whilst performing 6 × 800 m running intervals, measured the highest rates of fat oxidation yet reported in humans. Peak fat oxidation rates measured at 86.4 ± 6.2%VO2max were 1.58 ± 0.33 g/min with 30% of subjects achieving >1.85 g/min. These studies challenge the prevailing doctrine that carbohydrates are the predominant oxidized fuel during high-intensity exercise. We recently found that 30% of middle-aged competitive athletes presented with pre-diabetic glycemic values while on an HCLF diet, which was reversed on LCHF. We speculate that these rapid changes between diet, insulin, glucose homeostasis, and fat oxidation might be linked by diet-induced changes in mitochondrial function and insulin action. Together, we demonstrate evidence that challenges the current crossover concept and demonstrate evidence that a LCHF diet may also reverse features of pre-diabetes and future metabolic disease risk, demonstrating the impact of dietary choice has extended beyond physical performance even in athletic populations.
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Affiliation(s)
- T. D. Noakes
- Department of Medical and Wellness Science, Cape Peninsula University of Technology, Cape Town, South Africa
| | - P. J. Prins
- Department of Exercise Science, Grove City College, Grove City, PA, United States
| | - J. S. Volek
- Department of Human Sciences, The Ohio State University, Columbus, OH, United States
| | - D. P. D’Agostino
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, United States
- Human Healthspan, Resilience and Performance, Institute of Human and Machine Cognition, Pensacola, FL, United States
| | - A. P. Koutnik
- Human Healthspan, Resilience and Performance, Institute of Human and Machine Cognition, Pensacola, FL, United States
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Monedero J, Duff C, Egan B. Dietary Intakes and the Risk of Low Energy Availability in Male and Female Advanced and Elite Rock Climbers. J Strength Cond Res 2023; 37:e8-e15. [PMID: 35836334 DOI: 10.1519/jsc.0000000000004317] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Monedero, J, Duff, C, and Egan, B. Dietary intakes and the risk of low energy availability in male and female advanced and elite rock climbers. J Strength Cond Res 37(3): e8-e15, 2023-There is a culture among rock climbers of striving to maintain low body mass and percentage body fat to enhance performance. Diet practices based on this belief might lead to increased risk of low energy availability (LEA) or eating disorders (EDs). Twenty-five advanced or elite rock climbers (male, n = 14; female, n = 11) had body composition measured, completed 4-day food intake and physical activity diaries while wearing an accelerometer and heart rate monitor, and completed the Eating Attitudes Test (EAT)-26 and the Low Energy Availability in Females Questionnaire (LEAF-Q; n = 11 female subjects only). EAT-26 scores of 3.5 (1.8, 7.0) [median (IQR)] and 9.3 ± 6.4 (mean ± SD ) for male and female subjects, respectively, indicated low risk of ED in this cohort, but 4 female subjects were at high risk of LEA according to LEAF-Q scores. Suboptimal (<45 kcal·kg·FFM -1 ·d -1 ) and LEA (<30 kcal·kg·FFM -1 ·d -1 ) were evident in 88 and 28%, respectively, of climbers. However, only the female climbers had energy intakes (1775 ± 351 kcal·d -1 ) significantly lower than their calculated energy requirements (2056 ± 254 kcal·d -1 ; p = 0.006). In all subjects, carbohydrate intakes were lower (male subjects: 3.8 ± 1.2 g·kg -1 ·d -1 , p = 0.002; female subjects: 3.4 ± 0.7 g·kg -1 ·d -1 , p < 0.001), and fat intakes were higher (male subjects: 1.6 ± 0.5 g·kg -1 ·d -1 , p < 0.001; female subjects: 1.4 ± 0.4 g·kg -1 ·day -1 , p < 0.001) than current sports nutrition recommendations, and inadequate intakes of calcium, magnesium, and vitamin D were observed. Female subjects specifically had lower than recommended intakes of protein and iron. These results show that advanced and elite rock climbers have a high prevalence of LEA and have a risk of having nutritional deficiencies as result of their diet.
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Affiliation(s)
- Javier Monedero
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
- Department of Clinical Sciences and Nutrition, University of Chester, Chester, England; and
| | - Christina Duff
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Brendan Egan
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
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Iwayama K, Tanabe Y, Yajima K, Tanji F, Onishi T, Takahashi H. Preexercise High-Fat Meal Following Carbohydrate Loading Attenuates Glycogen Utilization During Endurance Exercise in Male Recreational Runners. J Strength Cond Res 2023; 37:661-668. [PMID: 36165996 DOI: 10.1519/jsc.0000000000004311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Iwayama, K, Tanabe, Y, Yajima, K, Tanji, F, Onishi, T, and Takahashi, H. Preexercise high-fat meal following carbohydrate loading attenuates glycogen utilization during endurance exercise in male recreational runners. J Strength Cond Res 37(3): 661-668, 2023-This study aimed to investigate whether one preexercise high-fat meal can increase glycogen conservation during endurance exercise, as compared with one preexercise high-carbohydrate meal. Ten young male recreational runners (22.0 ± 0.6 years; 171.3 ± 0.9 cm; 58.3 ± 1.9 kg; maximal oxygen uptake [V̇ o2 max], 62.0 ± 1.6 ml·kg -1 ·min -1 ) completed 2 exercise trials after high-carbohydrate loading: eating a high-carbohydrate (CHO; 7% protein, 13% fat, 80% carbohydrate) meal or eating a high-fat (FAT; 7% protein, 42% fat, 52% carbohydrate) meal 3.5 hours before exercise. The order of the 2 trials was randomized, and the interval between trials was at least 1 week. The experimental exercise consisted of running on a treadmill for 60 minutes at 95% of each subject's lactate threshold. Muscle and liver glycogen content were assessed using noninvasive carbon magnetic resonance spectroscopy before the experimental meal as well as before and after exercise; respiratory gases were measured continuously during exercise. The respiratory exchange ratio during exercise was statistically lower in the FAT trial than in the CHO trial ( p < 0.01). In addition, muscle ( p < 0.05) and liver ( p < 0.05) glycogen utilization during exercise was less in the FAT trial than in the CHO trial. Therefore, one high-fat meal following carbohydrate loading reduced muscle and liver glycogen use during the 60-minute exercise. These results suggest that this dietary approach may be applied as a strategy to optimize energy utilization during endurance exercise.
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Affiliation(s)
- Kaito Iwayama
- Faculty of Budo and Sport Studies, Tenri University, Nara, Japan
| | - Yoko Tanabe
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Katsuhiko Yajima
- Department of Nutritional Physiology, Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Fumiya Tanji
- Sport Medical Science Research Institute, Tokai University, Kanagawa, Japan ; and
| | - Takahiro Onishi
- Medical Center, Japan Institute of Sports Sciences, Tokyo, Japan
| | - Hideyuki Takahashi
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
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12
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Saris CGJ, Timmers S. Ketogenic diets and Ketone suplementation: A strategy for therapeutic intervention. Front Nutr 2022; 9:947567. [PMID: 36458166 PMCID: PMC9705794 DOI: 10.3389/fnut.2022.947567] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 10/13/2022] [Indexed: 07/24/2023] Open
Abstract
Ketogenic diets and orally administered exogenous ketone supplements are strategies to increase serum ketone bodies serving as an alternative energy fuel for high energy demanding tissues, such as the brain, muscles, and the heart. The ketogenic diet is a low-carbohydrate and fat-rich diet, whereas ketone supplements are usually supplied as esters or salts. Nutritional ketosis, defined as serum ketone concentrations of ≥ 0.5 mmol/L, has a fasting-like effect and results in all sorts of metabolic shifts and thereby enhancing the health status. In this review, we thus discuss the different interventions to reach nutritional ketosis, and summarize the effects on heart diseases, epilepsy, mitochondrial diseases, and neurodegenerative disorders. Interest in the proposed therapeutic benefits of nutritional ketosis has been growing the past recent years. The implication of this nutritional intervention is becoming more evident and has shown interesting potential. Mechanistic insights explaining the overall health effects of the ketogenic state, will lead to precision nutrition for the latter diseases.
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Affiliation(s)
- Christiaan G. J. Saris
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Center for Mitochondrial Medicine, Nijmegen, Netherlands
| | - Silvie Timmers
- Department of Human and Animal Physiology, Wageningen University, Wageningen, Netherlands
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13
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Koerich ACC, Borszcz FK, Thives Mello A, de Lucas RD, Hansen F. Effects of the ketogenic diet on performance and body composition in athletes and trained adults: a systematic review and Bayesian multivariate multilevel meta-analysis and meta-regression. Crit Rev Food Sci Nutr 2022; 63:11399-11424. [PMID: 35757868 DOI: 10.1080/10408398.2022.2090894] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This systematic review with meta-analysis aimed to determine the effects of the ketogenic diet (KD) against carbohydrate (CHO)-rich diets on physical performance and body composition in trained individuals. The MEDLINE, EMBASE, CINAHL, SPORTDiscus, and The Cochrane Library were searched. Randomized and non-randomized controlled trials in athletes/trained adults were included. Meta-analytic models were carried out using Bayesian multilevel models. Eighteen studies were included providing estimates on cyclic exercise modes and strength one-maximum repetition (1-RM) performances and for total, fat, and free-fat masses. There were more favorable effects for CHO-rich than KD on time-trial performance (mode [95% credible interval]; -3.3% [-8.5%, 1.7%]), 1-RM (-5.7% [-14.9%, 2.6%]), and free-fat mass (-0.8 [-3.4, 1.9] kg); effects were more favorable to KD on total (-2.4 [-6.2, 1.8] kg) and fat mass losses (-2.4 [-5.4, 0.2] kg). Likely modifying effects on cyclic performance were the subject's sex and VO2max, intervention and performance durations, and mode of exercise. The intervention duration and subjects' sex were likely to modify effects on total body mass. KD can be a useful strategy for total and fat body losses, but a small negative effect on free-fat mass was observed. KD was not suitable for enhancing strength 1-RM or high-intensity cyclic performances.
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Affiliation(s)
- Ana Clara C Koerich
- Department of Nutrition, Health Sciences Center, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, Santa Catarina, Brazil
| | - Fernando Klitzke Borszcz
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, University Campus, Pantanal, Florianópolis, Santa Catarina, Brazil
| | - Arthur Thives Mello
- Department of Nutrition, Health Sciences Center, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, Santa Catarina, Brazil
| | - Ricardo Dantas de Lucas
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, University Campus, Pantanal, Florianópolis, Santa Catarina, Brazil
| | - Fernanda Hansen
- Department of Nutrition, Health Sciences Center, Federal University of Santa Catarina, University Campus, Trindade, Florianópolis, Santa Catarina, Brazil
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14
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Zdzieblik D, Friesenborg H, Gollhofer A, König D. A high carbohydrate diet with a low glycaemic index improves training effects in male endurance athletes. Int J Food Sci Nutr 2022; 73:965-972. [PMID: 35758204 DOI: 10.1080/09637486.2022.2091525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The present study investigated the effect of a 4-week high fat low carbohydrate (HFLC-G) versus high carbohydrate low glycaemic (LGI-G) or high glycaemic (HGI-G) diet on power output at lactate thresholds, peak oxygen uptake and peak performance during an incremental cycle test in 28 male endurance athletes. All participants showed improved levels of power output at the lactate thresholds with a more pronounced effect in the HFLC-G and LGI-G. In the HFLC-G peak performance (-11.6 ± 16.3 W) decreased, while in the LGI-G (9.20 ± 13.8 W) and HGI-G (9.89 ± 12.8 W) peak performance increased (p = 0.009). In summary, the LGI-G showed comparable training adaptations as the HFLC-G at submaximal intensities without limiting the ability to perform at high intensities. Compared to a HFLC and HGI diet, the LGI diet in this study seemed to be advantageous during submaximal and high intensities resulting from an improved metabolic flexibility.
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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
- Department for Nutrition, Exercise and Health, Centre for Sports Science and University Sports, University of Vienna, Vienna, Austria.,Department for Nutrition, Exercise and Health, Faculty of Life Sciences, University of Vienna, Vienna, Austria
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15
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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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16
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Beyond the Calorie Paradigm: Taking into Account in Practice the Balance of Fat and Carbohydrate Oxidation during Exercise? Nutrients 2022; 14:nu14081605. [PMID: 35458167 PMCID: PMC9027421 DOI: 10.3390/nu14081605] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 02/04/2023] Open
Abstract
Recent literature shows that exercise is not simply a way to generate a calorie deficit as an add-on to restrictive diets but exerts powerful additional biological effects via its impact on mitochondrial function, the release of chemical messengers induced by muscular activity, and its ability to reverse epigenetic alterations. This review aims to summarize the current literature dealing with the hypothesis that some of these effects of exercise unexplained by an energy deficit are related to the balance of substrates used as fuel by the exercising muscle. This balance of substrates can be measured with reliable techniques, which provide information about metabolic disturbances associated with sedentarity and obesity, as well as adaptations of fuel metabolism in trained individuals. The exercise intensity that elicits maximal oxidation of lipids, termed LIPOXmax, FATOXmax, or FATmax, provides a marker of the mitochondrial ability to oxidize fatty acids and predicts how much fat will be oxidized over 45–60 min of low- to moderate-intensity training performed at the corresponding intensity. LIPOXmax is a reproducible parameter that can be modified by many physiological and lifestyle influences (exercise, diet, gender, age, hormones such as catecholamines, and the growth hormone-Insulin-like growth factor I axis). Individuals told to select an exercise intensity to maintain for 45 min or more spontaneously select a level close to this intensity. There is increasing evidence that training targeted at this level is efficient for reducing fat mass, sparing muscle mass, increasing the ability to oxidize lipids during exercise, lowering blood pressure and low-grade inflammation, improving insulin secretion and insulin sensitivity, reducing blood glucose and HbA1c in type 2 diabetes, and decreasing the circulating cholesterol level. Training protocols based on this concept are easy to implement and accept in very sedentary patients and have shown an unexpected efficacy over the long term. They also represent a useful add-on to bariatric surgery in order to maintain and improve its weight-lowering effect. Additional studies are required to confirm and more precisely analyze the determinants of LIPOXmax and the long-term effects of training at this level on body composition, metabolism, and health.
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17
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Pramsohler S, Burtscher M, Rausch L, Netzer NC. Weight Loss and Fat Metabolism during Multi-Day High-Altitude Sojourns: A Hypothesis Based on Adipocyte Signaling. Life (Basel) 2022; 12:life12040545. [PMID: 35455035 PMCID: PMC9026814 DOI: 10.3390/life12040545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/15/2022] [Accepted: 04/01/2022] [Indexed: 11/16/2022] Open
Abstract
Several publications and random observations have reported weight loss in high-altitude sojourners of both sexes. This could be a result of multiple adaptations, which hypoxia and mountaineering provoke on a cellular and organic level. Several publications have discussed the effect on appetite-regulating hormones to be one of the main contributing factors. We aimed to review the available data and show the current state of knowledge regarding nutritional aspects in high altitude with a special focus on fatty dietary forms. To reach this aim we conducted a literature search via PubMed according to the PRISMA 2020 protocol to identify relevant studies. We found that very few studies cover this field with scientifically satisfying evidence. For final analysis, reviews as well as papers that were not clearly related to the topic were excluded. Six articles were included discussing hormonal influences and the impact of exercise on appetite regulation as well as genetic factors altering metabolic processes at altitude. Leptin expression seems to be the biggest contributor to appetite reduction at altitude with an initial increase followed by a decrease in the course of time at high altitude. Its expression is greatly dependent on the amount of white adipose tissue. Since the expression of leptin is associated with an increased β-oxidation of fatty acids, a high-fat diet could be advantageous at a certain time point in the course of high-altitude sojourns.
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Affiliation(s)
- Stephan Pramsohler
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, 83043 Bad Aibling, Germany;
- Institute of Sports Science, University Innsbruck, 6020 Innsbruck, Austria; (M.B.); (L.R.)
- Department Medicine, Division of Sports Medicine and Rehabilitation, University Hospitals, 89070 Ulm, Germany
- Correspondence: ; Tel.: +49-(0)163-628-6366
| | - Martin Burtscher
- Institute of Sports Science, University Innsbruck, 6020 Innsbruck, Austria; (M.B.); (L.R.)
| | - Linda Rausch
- Institute of Sports Science, University Innsbruck, 6020 Innsbruck, Austria; (M.B.); (L.R.)
| | - Nikolaus C. Netzer
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, 83043 Bad Aibling, Germany;
- Institute of Sports Science, University Innsbruck, 6020 Innsbruck, Austria; (M.B.); (L.R.)
- Department Medicine, Division of Sports Medicine and Rehabilitation, University Hospitals, 89070 Ulm, Germany
- Institute of Mountain Emergency Medicine, Eurac Research, 39100 Bozen, Italy
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18
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UCHIZAWA A, FUNAYAMA A, OSUMI H, ENOMOTO Y, ZHANG S, TOKUYAMA K, OMI N, SAGAYAMA H. Food Quotient Assessments Using One-Week Dietary Records and Food Frequency Questionnaires of Young Japanese Runners. J Nutr Sci Vitaminol (Tokyo) 2022; 68:47-54. [DOI: 10.3177/jnsv.68.47] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Akiko UCHIZAWA
- Graduate School of Comprehensive Human Science, University of Tsukuba
| | - Airi FUNAYAMA
- Graduate School of Comprehensive Human Science, University of Tsukuba
| | - Haruka OSUMI
- Graduate School of Comprehensive Human Science, University of Tsukuba
| | | | - Simeng ZHANG
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba
| | - Kumpei TOKUYAMA
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba
| | - Naomi OMI
- Faculty of Health and Sport Sciences, University of Tsukuba
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19
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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: 14] [Impact Index Per Article: 7.0] [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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20
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New Horizons in Carbohydrate Research and Application for Endurance Athletes. Sports Med 2022; 52:5-23. [PMID: 36173597 PMCID: PMC9734239 DOI: 10.1007/s40279-022-01757-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2022] [Indexed: 12/15/2022]
Abstract
The importance of carbohydrate as a fuel source for exercise and athletic performance is well established. Equally well developed are dietary carbohydrate intake guidelines for endurance athletes seeking to optimize their performance. This narrative review provides a contemporary perspective on research into the role of, and application of, carbohydrate in the diet of endurance athletes. The review discusses how recommendations could become increasingly refined and what future research would further our understanding of how to optimize dietary carbohydrate intake to positively impact endurance performance. High carbohydrate availability for prolonged intense exercise and competition performance remains a priority. Recent advances have been made on the recommended type and quantity of carbohydrates to be ingested before, during and after intense exercise bouts. Whilst reducing carbohydrate availability around selected exercise bouts to augment metabolic adaptations to training is now widely recommended, a contemporary view of the so-called train-low approach based on the totality of the current evidence suggests limited utility for enhancing performance benefits from training. Nonetheless, such studies have focused importance on periodizing carbohydrate intake based on, among other factors, the goal and demand of training or competition. This calls for a much more personalized approach to carbohydrate recommendations that could be further supported through future research and technological innovation (e.g., continuous glucose monitoring). Despite more than a century of investigations into carbohydrate nutrition, exercise metabolism and endurance performance, there are numerous new important discoveries, both from an applied and mechanistic perspective, on the horizon.
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21
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Comparing Acute, High Dietary Protein and Carbohydrate Intake on Transcriptional Biomarkers, Fuel Utilisation and Exercise Performance in Trained Male Runners. Nutrients 2021; 13:nu13124391. [PMID: 34959943 PMCID: PMC8706924 DOI: 10.3390/nu13124391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/17/2022] Open
Abstract
Manipulating dietary macronutrient intake may modulate adaptive responses to exercise, and improve endurance performance. However, there is controversy as to the impact of short-term dietary modification on athletic performance. In a parallel-groups, repeated measures study, 16 trained endurance runners (maximal oxygen uptake (V˙O2max): 64.2 ± 5.6 mL·kg-1·min-1) were randomly assigned to, and provided with, either a high-protein, reduced-carbohydrate (PRO) or a high-carbohydrate (CHO) isocaloric-matched diet. Participants maintained their training load over 21-consecutive days with dietary intake consisting of 7-days habitual intake (T1), 7-days intervention diet (T2) and 7-days return to habitual intake (T3). Following each 7-day dietary period (T1-T3), a micro-muscle biopsy was taken for assessment of gene expression, before participants underwent laboratory assessment of a 10 km treadmill run at 75% V˙O2max, followed by a 95% V˙O2max time to exhaustion (TTE) trial. The PRO diet resulted in a modest change (1.37-fold increase, p = 0.016) in AMPK expression, coupled with a significant increase in fat oxidation (0.29 ± 0.05 to 0.59 ± 0.05 g·min-1, p < 0.0001). However, a significant reduction of 23.3% (p = 0.0003) in TTE post intervention was observed; this reverted back to pre levels following a return to the habitual diet. In the CHO group, whilst no change in sub-maximal fuel utilisation occurred at T2, a significant 6.5% increase in TTE performance (p = 0.05), and a modest, but significant, increase in AMPK (p = 0.042) and PPAR (p = 0.029) mRNA expression compared to T1 were observed; with AMPK (p = 0.011) and PPAR (p = 0.044) remaining significantly elevated at T3. In conclusion, a 7-day isocaloric high protein diet significantly compromised high intensity exercise performance in trained runners with no real benefit on gene markers of training adaptation. A significant increase in fat oxidation during submaximal exercise was observed post PRO intervention, but this returned to pre levels once the habitual diet was re-introduced, suggesting that the response was driven via fuel availability rather than cellular adaptation. A short-term high protein, low carbohydrate diet in combination with endurance training is not preferential for endurance running performance.
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22
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Effects of High-Intensity Interval Training on Inflammatory Biomarkers in Patients with Type 2 Diabetes. A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182312644. [PMID: 34886369 PMCID: PMC8656922 DOI: 10.3390/ijerph182312644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022]
Abstract
Background: Due to the prevalence and incidence worldwide of type 2 diabetes, and the significant role physical activity plays in these patients, a systematic review has been conducted to find out the effects that high-intensity interval training has on inflammatory biomarkers in subjects with type 2 diabetes. This project aims to determine the effect this training modality has on inflammatory biomarkers, in addition to observing its effects on the values of body composition and determining if this is a more effective, less effective or equally effective alternative to standard aerobic or resistance training. Methods: A search was conducted in the months of November and December 2020 on different databases: Pubmed, WoS and PEDro. A protocol for this systematic review was registered in PROSPERO (Registration number: CRD42021281186). The studies selected met the previously defined inclusion criteria, and the methodological quality of the papers used was evaluated according to the Downs and Black Checklist. Results: Out of 46 studies found, seven were included. The most relevant data concerning the characteristics of the clinical trials and HIIT characteristics, the values of body composition and the biomarkers under study were extracted from each study. Moreover, the results obtained from the different studies were described. Conclusions: HIIT could have an effect on inflammatory biomarkers. There is likely to be a relationship between changes in inflammatory profile and fat loss. A controlled diet may be a good complement to reduce the inflammatory profile. Further studies are required to determine whether HIIT is a better, worse or an equivalent alternative to medium-intensity aerobic exercise to improve the inflammatory profile.
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Brooke NK, Cosio-Lima L. Nutrition in Cycling. Phys Med Rehabil Clin N Am 2021; 33:159-172. [PMID: 34798997 DOI: 10.1016/j.pmr.2021.08.011] [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] [Indexed: 11/17/2022]
Abstract
Cycling is predominantly an endurance sport in which fuel utilization for energy production relies on the availability and delivery of oxygen to exercising muscle. Nutrition and training interventions to improve endurance performance are continually evolving, but ultimately, prescription should aim to generate improvements in cycling power and velocity while prioritizing athlete health and well-being. The wide range of cycling events and the different environments in which events take place pose a variety of nutrition-related challenges for cyclists. This review addresses some of these challenges and highlights recent advancements in nutrition for cycling performance.
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Affiliation(s)
- Namrita Kumar Brooke
- Department of Movement Sciences and Health, University of West Florida, 11000 University Parkway Building 782/220, Pensacola, FL 32514, USA.
| | - Ludmila Cosio-Lima
- Department of Movement Sciences and Health, University of West Florida, 11000 University Parkway Building 782/220, Pensacola, FL 32514, USA
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24
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Small SD, Margolis LM. Impact of Dietary Carbohydrate Restriction versus Energy Restriction on Exogenous Carbohydrate Oxidation during Aerobic Exercise. Adv Nutr 2021; 13:S2161-8313(22)00076-X. [PMID: 34788795 PMCID: PMC8970824 DOI: 10.1093/advances/nmab124] [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: 02/01/2023] Open
Abstract
Individuals with high physical activity levels, such as athletes and military personnel, are likely to experience periods of low muscle glycogen content. Reductions in glycogen stores are associated with impaired physical performance. Lower glycogen stores in these populations are likely due to sustained aerobic exercise coupled with sub-optimal carbohydrate or energy intake. Consuming exogenous carbohydrate during aerobic exercise may be an effective intervention to sustain physical performance during periods of low glycogen. However, research is limited in the area of carbohydrate recommendations to fuel performance during periods of sub-optimal carbohydrate and energy intake. Additionally, the studies that have investigated the effects of low glycogen stores on exogenous carbohydrate oxidation have yielded conflicting results. Discrepancies between studies may be the result of glycogen stores being lowered by restricting carbohydrate or restricting energy intake. This narrative review discusses the influence of low glycogen status resulting from carbohydrate restriction versus energy restriction on exogenous carbohydrate oxidation and examines the potential mechanism resulting in divergent responses in exogenous carbohydrate oxidation. Results from this review indicate that rates of exogenous carbohydrate oxidation can be maintained when glycogen content is lower following carbohydrate restrictions, but may be reduced following energy restriction. Reductions in exogenous carbohydrate oxidation following energy restriction appear to result from lower insulin sensitivity and glucose uptake. Exogenous carbohydrate may thus be an effective intervention to sustain performance following short-term energy adequate carbohydrate restriction, but may not be an effective ergogenic aid when glycogen stores are low due to energy restriction.
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Affiliation(s)
- Stephanie D Small
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA,Oak Ridge Institute of Science and Education, Oak Ridge, TN, USA
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Burke LM. Nutritional approaches to counter performance constraints in high-level sports competition. Exp Physiol 2021; 106:2304-2323. [PMID: 34762329 PMCID: PMC9299184 DOI: 10.1113/ep088188] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022]
Abstract
New Findings What is the topic of this review? The nutritional strategies that athletes use during competition events to optimize performance and the reasons they use them. What advances does it highlight? A range of nutritional strategies can be used by competitive athletes, alone or in combination, to address various event‐specific factors that constrain event performance. Evidence for such practices is constantly evolving but must be combined with understanding of the complexities of real‐life sport for optimal implementation.
Abstract High‐performance athletes share a common goal despite the unique nature of their sport: to pace or manage their performance to achieve the highest sustainable outputs over the duration of the event. Periodic or sustained decline in the optimal performance of event tasks, involves an interplay between central and peripheral phenomena that can often be reduced or delayed in onset by nutritional strategies. Contemporary nutrition practices undertaken before, during or between events include strategies to ensure the availability of limited muscle fuel stores. This includes creatine supplementation to increase muscle phosphocreatine content and consideration of the type, amount and timing of dietary carbohydrate intake to optimize muscle and liver glycogen stores or to provide additional exogenous substrate. Although there is interest in ketogenic low‐carbohydrate high‐fat diets and exogenous ketone supplements to provide alternative fuels to spare muscle carbohydrate use, present evidence suggests a limited utility of these strategies. Mouth sensing of a range of food tastants (e.g., carbohydrate, quinine, menthol, caffeine, fluid, acetic acid) may provide a central nervous system derived boost to sports performance. Finally, despite decades of research on hypohydration and exercise capacity, there is still contention around their effect on sports performance and the best guidance around hydration for sporting events. A unifying model proposes that some scenarios require personalized fluid plans while others might be managed by an ad hoc approach (ad libitum or thirst‐driven drinking) to fluid intake.
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Affiliation(s)
- Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
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26
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Bromley LE, Horvath PJ, Bennett SE, Weinstock-Guttman B, Rideout TC, Browne RW, Ray AD. Three-Day Dietary Manipulation in Multiple Sclerosis: Exercise and Fatigue Outcomes. Int J MS Care 2021; 23:199-205. [PMID: 34720759 DOI: 10.7224/1537-2073.2020-036] [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: 11/18/2022]
Abstract
Background In persons with multiple sclerosis (MS), the effect of nutrition on exercise performance and fatigue remains unknown. The objective was to determine whether a 3-day diet high in triglycerides (FAT) compared with a 3-day diet high in carbohydrates (CARB) would improve fatigue and exercise performance in persons with MS. Methods A randomized controlled crossover design was incorporated to study FAT versus CARB on submaximal cycling endurance (60% of peak oxygen consumption), substrate utilization, and fatigue in 12 persons with mild-to-moderate MS (Expanded Disability Status Scale score, 2.0-5.0) and 12 age- and sex-matched controls. Results There were no differences in cycling time between diets in either group (P = .29). The MS group had no changes in fatigue between diets (P = .64); the control group demonstrated increased total mental fatigue after FAT (P = .05). The control group increased carbohydrate oxidation by 24% at rest and 13% during exercise after CARB. Similarly, the control group significantly increased fat oxidation after FAT by 22% at rest and 68% during exercise (P = .01). These changes were not seen in the MS group. Compared with controls, persons with MS oxidized approximately 50% less fat during exercise after FAT (P = .05). Conclusions Neither CARB nor FAT altered submaximal exercise performance or baseline fatigue in the MS group. The results suggest that persons with MS are unable to adapt to dietary changes and oxidize fatty acids as efficiently as controls.
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Affiliation(s)
- Lacey E Bromley
- Department of Physical Therapy, D'Youville, Buffalo, NY, USA (LEB)
| | - Peter J Horvath
- Department of Exercise and Nutritional Sciences (PJH, TCR), University at Buffalo, Buffalo, NY
| | - Susan E Bennett
- Department of Rehabilitation Science (SEB), University at Buffalo, Buffalo, NY, USA
| | | | - Todd C Rideout
- Department of Exercise and Nutritional Sciences (PJH, TCR), University at Buffalo, Buffalo, NY
| | - Richard W Browne
- Department of Biotechnical and Clinical Laboratory Sciences (RWB), University at Buffalo, Buffalo, NY, USA
| | - Andrew D Ray
- Department of Cancer Prevention and Control, Roswell Park Cancer Center, Buffalo NY, USA (ADR)
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Effects of a Low-Carbohydrate High-Fat Diet Combined with High-Intensity Interval Training on Body Composition and Maximal Oxygen Uptake: A Systematic Review and Meta-Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182010740. [PMID: 34682481 PMCID: PMC8535842 DOI: 10.3390/ijerph182010740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/04/2021] [Accepted: 10/06/2021] [Indexed: 12/13/2022]
Abstract
The low-carbohydrate high-fat (LCHF) diet has recently been subject to attention on account of its reported influences on body composition and physical performance. However, the combined effect of LCHF with high-intensity interval training (HIIT) is unclear. A systematic review and meta-analysis were conducted to explore the effect of the LCHF diet combined with HIIT on human body composition (i.e., body weight (BM), body mass index (BMI), fat mass (FM), body fat percentage (BFP), fat-free mass (FFM)) and maximal oxygen uptake (VO2max). Online libraries (PubMed, Web of Science, EMBASE, Cochrane Library, EBSCO, CNKI, Wan Fang) were used to search initial studies until July 2021, from which 10 out of 2440 studies were included. WMD served as the effect size with a confidence interval value of 95%. The results of meta-analysis showed a significant reduction in BM (WMD = −5.299; 95% CI: −7.223, −3.376, p = 0.000), BMI (WMD = −1.150; 95% CI: −2.225, −0.075, p = 0.036), BFP (WMD = −2.787; 95% CI: −4.738, −0.835, p = 0.005) and a significant increase in VO2max (WMD = 3.311; 95% CI: 1.705, 4.918, p = 0.000), while FM (WMD = −2.221; 95% CI: −4.582, 0.139, p = 0.065) and FFM (WMD = 0.487; 95% CI: −3.512, 4.469, p = 0.814) remained unchanged. In conclusion, the LCHF diet combined with HIIT can reduce weight and fat effectively. This combination is sufficient to prevent muscle mass loss during LCHF, and further enhance VO2max. Further research might be required to clarify the effect of other types of exercise on body composition and physical performance during LCHF.
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28
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Zamir A, Ben-Zeev T, Hoffman JR. Manipulation of Dietary Intake on Changes in Circulating Testosterone Concentrations. Nutrients 2021; 13:3375. [PMID: 34684376 PMCID: PMC8538516 DOI: 10.3390/nu13103375] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 12/22/2022] Open
Abstract
Elevations in the circulating concentration of androgens are thought to have a positive effect on the anabolic processes leading to improved athletic performance. Anabolic-androgenic steroids have often been used by competitive athletes to augment this effect. Although there has been concerted effort on examining how manipulating training variables (e.g., intensity and volume of training) can influence the androgen response to exercise, there has been much less effort directed at understanding how changes in both macronutrient and micronutrient intake can impact the androgen response. Thus, the focus of this review is to examine the effect that manipulating energy and nutrient intake has on circulating concentrations of testosterone and what the potential mechanism is governing these changes.
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Affiliation(s)
| | | | - Jay R. Hoffman
- Department of Physical Therapy, Faculty of Health Sciences, Ariel University, 40700 Ariel, Israel; (A.Z.); (T.B.-Z.)
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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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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; 13:2896. [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] [Grants] [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
| | - 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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Tam R, Flood VM, Beck KL, O'Connor HT, Gifford JA. Measuring the sports nutrition knowledge of elite Australian athletes using the Platform to Evaluate Athlete Knowledge of Sports Nutrition Questionnaire. Nutr Diet 2021; 78:535-543. [PMID: 34155780 DOI: 10.1111/1747-0080.12687] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 04/29/2021] [Accepted: 05/05/2021] [Indexed: 11/29/2022]
Abstract
AIMS To evaluate the nutrition knowledge of elite Australian athletes, and to obtain feedback from sports dietitians on the Platform to Evaluate Athlete Knowledge of Sports Nutrition Questionnaires' (PEAKS-NQ) suitability. METHODS Sports dietitians from the National Institute Network across Australia recruited athletes to complete the online, 50-item PEAKS-NQ which contained two sections (General Nutrition and Sports Nutrition). Sports dietitians provided feedback on the PEAKS-NQ using a 14-item questionnaire (with two open-ended items). The main outcome measures were nutrition knowledge score and tool suitability (usefulness, acceptability and feasibility) scores. For knowledge scores, independent t-tests, ANOVA and Chi-square tests were used to evaluate differences between groups. Suitability was evaluated using descriptive statistics. RESULTS Twelve sports dietitians from the National Institute Network in Australia recruited a convenience sample of 240 athletes (21.3 ± 4.3 years, 63.5% female, 63.3% competed internationally). Athletes scored 70.7 ± 10.5%, with better general vs sports nutrition knowledge. Females had higher overall scores (P < .001) with no differences for age or sport played. University-educated athletes scored higher than non-tertiary educated athletes (P = .004). Knowledge gaps were identified in fats (role and food sources), recovery nutrition and managing body composition. Sports dietitians rated suitability of PEAKS-NQ positively with complete agreement on 8 of 12 items. CONCLUSIONS Athletes have greater understanding of general nutrition compared to sports nutrition concepts and may benefit from education on applying nutrition in sports-specific contexts. Sports dietitians' responses showed PEAKS-NQ was a highly acceptable, feasible and useful measure.
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Affiliation(s)
- Ryan Tam
- Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Camperdown, Australia
| | - Victoria M Flood
- Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Camperdown, Australia.,Western Sydney Local Health District, Westmead Hospital, North Parramatta, Australia
| | - Kathryn L Beck
- College of Health, Massey University, Auckland, New Zealand
| | - Helen T O'Connor
- Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Camperdown, Australia
| | - Janelle A Gifford
- Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Camperdown, Australia
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Effects of a low-carbohydrate ketogenic diet on health parameters in resistance-trained women. Eur J Appl Physiol 2021; 121:2349-2359. [PMID: 34003364 DOI: 10.1007/s00421-021-04707-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 04/29/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE The aim of this study was to evaluate the effect of a ketogenic diet on blood pressure, visceral adipose tissue (VAT), bone mineral content (BMC), and bone mineral density (BMD) in trained women. METHODS Twenty-one resistance-trained women performed an 8-week resistance training program after a 3-week familiarization phase. Participants were randomly assigned to a non-ketogenic diet (n = 11, NKD) or ketogenic diet (n = 10, KD) group. Health parameters were measured before and after the nutritional intervention. Blood pressure was measured using a digital automatic monitor, while VAT, BMC, and BMD changes were measured by dual-energy X-ray absorptiometry. RESULTS There was a significant reduction in systolic blood pressure in KD (mean ± SD [IC 95%], P value, Hedges' g; - 6.3 ± 6.0 [- 10.5, - 2.0] mmHg, P = 0.009, g = - 0.81) but not in NKD (- 0.4 ± 8.9 [- 6.8, 6.0] mmHg, P = 0.890, g = - 0.04). The results on VAT showed no changes in both groups. The KD showed a small favorable effect on BMD (0.02 ± 0.02 [0.01, 0.03] g·cm-2, P = 0.014, g = 0.19) while NKD did not show significant changes (0.00 ± 0.02 [- 0.02, 0.02] g·cm-2, P = 0.886, g = 0.01). No differences in group or in the time × group interaction were found in any of the variables. CONCLUSIONS Consuming a low-carbohydrate high-fat KD in conjunction with a resistance training program might help to promote the improvement of health-related markers in resistance-trained women. Long-term studies are required to evaluate the superiority of a KD in comparison to a traditional diet.
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Gejl KD, Nybo L. Performance effects of periodized carbohydrate restriction in endurance trained athletes - a systematic review and meta-analysis. J Int Soc Sports Nutr 2021; 18:37. [PMID: 34001184 PMCID: PMC8127206 DOI: 10.1186/s12970-021-00435-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/22/2021] [Indexed: 11/10/2022] Open
Abstract
Endurance athletes typically consume carbohydrate-rich diets to allow for optimal performance during competitions and intense training. However, acute exercise studies have revealed that training or recovery with low muscle glycogen stimulates factors of importance for mitochondrial biogenesis in addition to favourable metabolic adaptations in trained athletes. Compromised training quality and particularly lower intensities in peak intervals seem to be a major drawback from dietary interventions with chronic carbohydrate (CHO) restriction. Therefore, the concept of undertaking only selected training sessions with restricted CHO availability (periodized CHO restriction) has been proposed for endurance athletes. However, the overall performance effect of this concept has not been systematically reviewed in highly adapted endurance-trained athletes. We therefore conducted a meta-analysis of training studies that fulfilled the following criteria: a) inclusion of females and males demonstrating a VO2max ≥ 55 and 60 ml · kg− 1 · min− 1, respectively; b) total intervention and training periods ≥ 1 week, c) use of interventions including training and/or recovery with periodized carbohydrate restriction at least three times per week, and d) measurements of endurance performance before and after the training period. The literature search resulted in 407 papers of which nine studies fulfilled the inclusion criteria. The subsequent meta-analysis demonstrated no overall effect of CHO periodization on endurance performance compared to control endurance training with normal (high) CHO availability (standardized mean difference = 0.17 [− 0.15, 0.49]; P = 0.29). Based on the available literature, we therefore conclude that periodized CHO restriction does not per se enhance performance in endurance-trained athletes. The review discusses different approaches to CHO periodization across studies with a focus on identifying potential physiological benefits.
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Affiliation(s)
- Kasper Degn Gejl
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Jurado-Fasoli L, Amaro-Gahete FJ, Merchan-Ramirez E, Labayen I, Ruiz JR. Relationships between diet and basal fat oxidation and maximal fat oxidation during exercise in sedentary adults. Nutr Metab Cardiovasc Dis 2021; 31:1087-1101. [PMID: 33549436 DOI: 10.1016/j.numecd.2020.11.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND AND AIMS To study the relationships between different dietary factors (i.e., energy, macronutrient and fatty acid intake, food group consumption, and dietary pattern) and basal fat oxidation (BFox) and maximal fat oxidation during exercise (MFO) in sedentary adults. METHOD AND RESULTS A total of 212 (n = 130 women; 32.4 ± 15.1 years) sedentary healthy adults took part in the present study. Information on the different dietary factors examined was gathered through a food frequency questionnaire and three nonconsecutive 24 h recalls. Energy and macronutrient intakes and food consumption were then estimated and dietary patterns calculated. BFox and MFO were measured by indirect calorimetry following standard procedures. Our study shows that dietary fiber intake was positively associated with BFox after taking into consideration the age, sex, and energy intake. A significant positive association between nut consumption and BFox was observed, which became nonsignificant after taking into consideration the age and energy intake. Fat intake and the dietary quality index (DQI), and the DQI for the Mediterranean diet were positively associated with MFO, which was attenuated after taking sex, age, and energy intake into consideration. CONCLUSION A higher dietary fiber intake and fat intake are associated with higher BFox and MFO, respectively, in sedentary adults. CLINICAL TRIALS ClinicalTrials.gov, ID: NCT02365129 (https://clinicaltrials.gov/ct2/show/study/NCT02365129) & ID: NCT03334357 (https://clinicaltrials.gov/ct2/show/NCT03334357).
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Affiliation(s)
- Lucas Jurado-Fasoli
- PROmoting FITness and Health through physical activity research group (PROFITH), Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, 18071, Granada, Spain; EFFECTS 262 Research Group, Department of Medical Physiology, School of Medicine. University of Granada, 18071, Granada, Spain.
| | - Francisco J Amaro-Gahete
- PROmoting FITness and Health through physical activity research group (PROFITH), Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, 18071, Granada, Spain; EFFECTS 262 Research Group, Department of Medical Physiology, School of Medicine. University of Granada, 18071, Granada, Spain
| | - Elisa Merchan-Ramirez
- PROmoting FITness and Health through physical activity research group (PROFITH), Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, 18071, Granada, Spain
| | - Idoia Labayen
- Institute for Innovation & Sustainable Development in Food Chain (IS-FOOD), Public University of Navarra, Campus de Arrosadía, 31008, Pamplona, Spain
| | - Jonatan R Ruiz
- PROmoting FITness and Health through physical activity research group (PROFITH), Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, 18071, Granada, Spain
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Shaw DM, Merien F, Braakhuis A, Maunder E, Dulson DK. Exogenous Ketone Supplementation and Keto-Adaptation for Endurance Performance: Disentangling the Effects of Two Distinct Metabolic States. Sports Med 2021; 50:641-656. [PMID: 31820376 DOI: 10.1007/s40279-019-01246-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ketone bodies (KB) provide an alternative energy source and uniquely modulate substrate metabolism during endurance exercise. Nutritional ketosis (blood KBs > 0.5 mM) can be achieved within minutes via exogenous ketone supplementation or days-to-weeks via conforming to a very low-carbohydrate, ketogenic diet (KD). In contrast to short-term (< 2 weeks) KD ingestion, chronic adherence (> 3 weeks) leads to a state of keto-adaptation. However, despite elevating blood KBs to similar concentrations, exogenous ketone supplementation and keto-adaptation are not similar metabolic states as they elicit diverse and distinct effects on substrate availability and metabolism during exercise; meaning that their influence on endurance exercise performance is different. In contrast to contemporary, high(er)-carbohydrate fuelling strategies, inducing nutritional ketosis is rarely ergogenic irrespective of origin and, in fact, can impair endurance performance. Nonetheless, exogenous ketone supplementation and keto-adaptation possess utility for select endurance events and individuals, thus warranting further research into their performance effects and potential strategies for their optimisation. It is critical, however, that future research considers the limitations of measuring blood KB concentrations and their utilisation, and assess the effect of nutritional ketosis on performance using exercise protocols reflective of real-world competition. Furthermore, to reliably assess the effects of keto-adaptation, rigorous dietary-training controls of sufficient duration should be prioritised.
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Affiliation(s)
- David M Shaw
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
| | - Fabrice Merien
- AUT-Roche Diagnostics Laboratory, School of Science, Auckland University of Technology, Auckland, New Zealand
| | - Andrea Braakhuis
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Ed Maunder
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Deborah K Dulson
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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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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Burén J, Ericsson M, Damasceno NRT, Sjödin A. A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial. Nutrients 2021; 13:nu13030814. [PMID: 33801247 PMCID: PMC8001988 DOI: 10.3390/nu13030814] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/23/2021] [Accepted: 02/26/2021] [Indexed: 02/06/2023] Open
Abstract
Ketogenic low-carbohydrate high-fat (LCHF) diets are popular among young, healthy, normal-weight individuals for various reasons. We aimed to investigate the effect of a ketogenic LCHF diet on low-density lipoprotein (LDL) cholesterol (primary outcome), LDL cholesterol subfractions and conventional cardiovascular risk factors in the blood of healthy, young, and normal-weight women. The study was a randomized, controlled, feeding trial with crossover design. Twenty-four women were assigned to a 4 week ketogenic LCHF diet (4% carbohydrates; 77% fat; 19% protein) followed by a 4 week National Food Agency recommended control diet (44% carbohydrates; 33% fat; 19% protein), or the reverse sequence due to the crossover design. Treatment periods were separated by a 15 week washout period. Seventeen women completed the study and treatment effects were evaluated using mixed models. The LCHF diet increased LDL cholesterol in every woman with a treatment effect of 1.82 mM (p < 0.001). In addition, Apolipoprotein B-100 (ApoB), small, dense LDL cholesterol as well as large, buoyant LDL cholesterol increased (p < 0.001, p < 0.01, and p < 0.001, respectively). The data suggest that feeding healthy, young, normal-weight women a ketogenic LCHF diet induces a deleterious blood lipid profile. The elevated LDL cholesterol should be a cause for concern in young, healthy, normal-weight women following this kind of LCHF diet.
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Affiliation(s)
- Jonas Burén
- Department of Food, Nutrition and Culinary Science, Umeå University, 90187 Umeå, Sweden;
- Department of Public Health and Clinical Medicine, Medicine, Umeå University, 90187 Umeå, Sweden
- Correspondence: ; Tel.: +46-90-7866560
| | - Madelene Ericsson
- Department of Medical Biosciences, Physiological Chemistry, Umeå University, 90187 Umeå, Sweden;
- Umeå Centre for Molecular Medicine, Umeå University, 90187 Umeå, Sweden
| | | | - Anna Sjödin
- Department of Food, Nutrition and Culinary Science, Umeå University, 90187 Umeå, Sweden;
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Determinants of Peak Fat Oxidation Rates During Cycling in Healthy Men and Women. Int J Sport Nutr Exerc Metab 2021; 31:227-235. [PMID: 33588373 DOI: 10.1123/ijsnem.2020-0262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/23/2020] [Accepted: 11/19/2020] [Indexed: 11/18/2022]
Abstract
This study explored lifestyle and biological determinants of peak fat oxidation (PFO) during cycle ergometry, using duplicate measures to account for day-to-day variation. Seventy-three healthy adults (age range: 19-63 years; peak oxygen consumption [V˙O2peak]: 42.4 [10.1] ml·kg BM-1·min-1; n = 32 women]) completed trials 7-28 days apart that assessed resting metabolic rate, a resting venous blood sample, and PFO by indirect calorimetry during an incremental cycling test. Habitual physical activity (combined heart rate accelerometer) and dietary intake (weighed record) were assessed before the first trial. Body composition was assessed 2-7 days after the second identical trial by dual-energy X-ray absorptiometry scan. Multiple linear regressions were performed to identify determinants of PFO (mean of two cycle tests). A total variance of 79% in absolute PFO (g·min-1) was explained with positive coefficients for V˙O2peak (strongest predictor), FATmax (i.e the % of V˙O2peak that PFO occurred at), and resting fat oxidation rate (g·min-1), and negative coefficients for body fat mass (kg) and habitual physical activity level. When expressed relative to fat-free mass, 64% of variance in PFO was explained: positive coefficients for FATmax (strongest predictor), V˙O2peak, and resting fat oxidation rate, and negative coefficients for male sex and fat mass. This duplicate design revealed that biological and lifestyle factors explain a large proportion of variance in PFO during incremental cycling. After accounting for day-to-day variation in PFO, V˙O2peak and FATmax were strong and consistent predictors of PFO.
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39
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Burke LM. Ketogenic low-CHO, high-fat diet: the future of elite endurance sport? J Physiol 2021; 599:819-843. [PMID: 32358802 PMCID: PMC7891323 DOI: 10.1113/jp278928] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/27/2020] [Indexed: 01/06/2023] Open
Abstract
The ability of ketogenic low-carbohydrate (CHO) high-fat (K-LCHF) diets to enhance muscle fat oxidation has led to claims that it is the 'future of elite endurance sport'. There is robust evidence that substantial increases in fat oxidation occur, even in elite athletes, within 3-4 weeks and possibly 5-10 days of adherence to a K-LCHF diet. Retooling of the muscle can double exercise fat use to ∼1.5 g min-1 , with the intensity of maximal rates of oxidation shifting from ∼45% to ∼70% of maximal aerobic capacity. Reciprocal reductions in CHO oxidation during exercise are clear, but current evidence to support the hypothesis of the normalization of muscle glycogen content with longer-term adaptation is weak. Importantly, keto-adaptation may impair the muscle's ability to use glycogen for oxidative fates, compromising the use of a more economical energy source when the oxygen supply becomes limiting and, thus, the performance of higher-intensity exercise (>80% maximal aerobic capacity). Even with moderate intensity exercise, individual responsiveness to K-LCHF is varied, with extremes at both ends of the performance spectrum. Periodisation of K-LCHF with high CHO availability might offer opportunities to restore capacity for higher-intensity exercise, but investigations of various models have failed to find a benefit over dietary approaches based on current sports nutrition guidelines. Endurance athletes who are contemplating the use of K-LCHF should undertake an audit of event characteristics and personal experiences to balance the risk of impaired performance of higher-intensity exercise with the likelihood of an unavoidable depletion of carbohydrate stores.
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Affiliation(s)
- Louise M. Burke
- Australian Institute of SportCanberra2616Australia
- Mary MacKillop Institute for Health ResearchAustralian Catholic UniversityMelbourne3000Australia
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40
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Bestard MA, Rothschild JA, Crocker GH. Effect of low- and high-carbohydrate diets on swimming economy: a crossover study. J Int Soc Sports Nutr 2020; 17:64. [PMID: 33298105 PMCID: PMC7724792 DOI: 10.1186/s12970-020-00392-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/10/2020] [Indexed: 11/28/2022] Open
Abstract
Background Swimming economy refers to the rate of energy expenditure relative to swimming speed of movement, is inversely related to the energetic cost of swimming, and is as a key factor influencing endurance swimming performance. The objective of this study was to determine if high-carbohydrate, low-fat (HCLF) and low-carbohydrate, high-fat (LCHF) diets affect energetic cost of submaximal swimming. Methods Eight recreational swimmers consumed two 3-day isoenergetic diets in a crossover design. Diets were tailored to individual food preferences, and macronutrient consumption was 69–16-16% and 16–67-18% carbohydrate-fat-protein for the HCLF and LCHF diets, respectively. Following each 3-day dietary intervention, participants swam in a flume at velocities associated with 50, 60, and 70% of their maximal aerobic capacity (VO2max). Expired breath was collected and analyzed while they swam which enabled calculation of the energetic cost of swimming. A paired t-test compared macronutrient distribution between HCLF and LCHF diets, while repeated-measures ANOVA determined effects of diet and exercise intensity on physiological endpoints. Results Respiratory exchange ratio was significantly higher in HCLF compared to LCHF (p = 0.003), but there were no significant differences in the rate of oxygen consumption (p = 0.499) or energetic cost of swimming (p = 0.324) between diets. Heart rate did not differ between diets (p = 0.712), but oxygen pulse, a non-invasive surrogate for stroke volume, was greater following the HCLF diet (p = 0.029). Conclusions A 3-day high-carbohydrate diet increased carbohydrate utilization but did not affect swimming economy at 50–70% VO2max. As these intensities are applicable to ultramarathon swims, future studies should use higher intensities that would be more relevant to shorter duration events.
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Affiliation(s)
- Merry A Bestard
- School of Kinesiology, Nutrition & Food Science, California State University, Los Angeles, 5151 State University Dr, Los Angeles, CA, 90032, USA
| | - Jeffrey A Rothschild
- School of Kinesiology, Nutrition & Food Science, California State University, Los Angeles, 5151 State University Dr, Los Angeles, CA, 90032, USA.,Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - George H Crocker
- School of Kinesiology, Nutrition & Food Science, California State University, Los Angeles, 5151 State University Dr, Los Angeles, CA, 90032, USA.
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Macedo RCO, Santos HO, Tinsley GM, Reischak-Oliveira A. Low-carbohydrate diets: Effects on metabolism and exercise - A comprehensive literature review. Clin Nutr ESPEN 2020; 40:17-26. [PMID: 33183532 DOI: 10.1016/j.clnesp.2020.07.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/29/2020] [Accepted: 07/30/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Low-carbohydrate diets (LCD) have gained substantial attention in recent years for their potential in health promotion and treatment of diseases, but they remain controversial in nutrition guidelines and exercise performance. Herein, through a literature review, we discuss the current evidence base by considering management of LCD and potential coupling of these dietary regiments with physical exercise. METHODS We performed a comprehensive literature review with no date limits as a means of including seminal to current studies. RESULTS Reduction of CHO intake decreases muscle glycogen, yielding greater fat oxidation and associated metabolic benefits. LCD may promote fat mass loss and regulation of biochemical parameters, such as lipid and glycemic biomarkers. The therapeutic potential of LCD towards noncommunicable diseases, particularly obesity and its comorbidities, is therefore reasonable as a dietary candidate in this context. Potential benefits to this approach are linked to enhancement of mitochondrial gene expression and mitochondrial biogenesis. As such, LCD may be a feasible tool in a 'periodized nutrition' for athletes and within clinical scenarios. Long-term observational follow-up studies have demonstrated increased mortality and cardiovascular implications of LCD. However, harmful associations may depend on the food source (e.g., animal-based vs. plant-based foods). CONCLUSION LCD may decrease body mass, waist circumference, and improve fat and carbohydrate metabolism. When combined with exercise, LCD seems to be an effective strategy in regulating metabolic factors of cardiovascular diseases. Conversely, LCD may be associated with higher mortality and metabolic dysregulations if it contains large amounts of animal-based foods, particularly saturated fat.
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Affiliation(s)
- Rodrigo C O Macedo
- University of Santa Cruz do Sul (UNISC), Santa Cruz do Sul, Brazil; Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
| | - Heitor O Santos
- School of Medicine, Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil.
| | - Grant M Tinsley
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX, USA
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Baur DA, Saunders MJ. Carbohydrate supplementation: a critical review of recent innovations. Eur J Appl Physiol 2020; 121:23-66. [PMID: 33106933 DOI: 10.1007/s00421-020-04534-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/12/2020] [Indexed: 12/29/2022]
Abstract
PURPOSE To critically examine the research on novel supplements and strategies designed to enhance carbohydrate delivery and/or availability. METHODS Narrative review. RESULTS Available data would suggest that there are varying levels of effectiveness based on the supplement/supplementation strategy in question and mechanism of action. Novel carbohydrate supplements including multiple transportable carbohydrate (MTC), modified carbohydrate (MC), and hydrogels (HGEL) have been generally effective at modifying gastric emptying and/or intestinal absorption. Moreover, these effects often correlate with altered fuel utilization patterns and/or glycogen storage. Nevertheless, performance effects differ widely based on supplement and study design. MTC consistently enhances performance, but the magnitude of the effect is yet to be fully elucidated. MC and HGEL seem unlikely to be beneficial when compared to supplementation strategies that align with current sport nutrition recommendations. Combining carbohydrate with other ergogenic substances may, in some cases, result in additive or synergistic effects on metabolism and/or performance; however, data are often lacking and results vary based on the quantity, timing, and inter-individual responses to different treatments. Altering dietary carbohydrate intake likely influences absorption, oxidation, and and/or storage of acutely ingested carbohydrate, but how this affects the ergogenicity of carbohydrate is still mostly unknown. CONCLUSIONS In conclusion, novel carbohydrate supplements and strategies alter carbohydrate delivery through various mechanisms. However, more research is needed to determine if/when interventions are ergogenic based on different contexts, populations, and applications.
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Affiliation(s)
- Daniel A Baur
- Department of Physical Education, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA.
| | - Michael J Saunders
- Department of Kinesiology, James Madison University, Harrisonburg, VA, 22801, USA
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43
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Valenzuela PL, Castillo-García A, Morales JS, Lucia A. Perspective: Ketone Supplementation in Sports-Does It Work? Adv Nutr 2020; 12:305-315. [PMID: 33094332 PMCID: PMC8243601 DOI: 10.1093/advances/nmaa130] [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] [Received: 06/12/2020] [Revised: 08/20/2020] [Accepted: 09/18/2020] [Indexed: 11/14/2022] Open
Abstract
Oral ketone supplements have gained popularity in recent years. There is biological rationale for a potential ergogenic effect of this type of supplement, as they might not only alter muscle fuel preference during exercise (and promote glycogen sparing, with potential benefits for endurance performance) but also favor cognition performance during exertion or muscle glycogen synthesis after exercise. However, as discussed in this Perspective, evidence to date does not support a benefit of acute ketone supplementation on sports performance, cognition, or muscle recovery [although further research with long-duration exercise (i.e., >60 min), is needed], and the evidence for chronic supplementation is sparse. In addition, acute intake of ketone supplements might be associated with gastrointestinal symptoms, and further research is warranted on the long-term safety of repeated use of ketone supplements. In summary, there is currently insufficient evidence to support the overall effectiveness of ketone supplements in sports.
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Affiliation(s)
| | | | - Javier S Morales
- Faculty of Sport Sciences, European University of Madrid, Madrid, Spain
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Stubbs BJ, Koutnik AP, Volek JS, Newman JC. From bedside to battlefield: intersection of ketone body mechanisms in geroscience with military resilience. GeroScience 2020; 43:1071-1081. [PMID: 33006708 PMCID: PMC8190215 DOI: 10.1007/s11357-020-00277-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022] Open
Abstract
Ketone bodies are endogenous metabolites that are linked to multiple mechanisms of aging and resilience. They are produced by the body when glucose availability is low, including during fasting and dietary carbohydrate restriction, but also can be consumed as exogenous ketone compounds. Along with supplying energy to peripheral tissues such as brain, heart, and skeletal muscle, they increasingly are understood to have drug-like protein binding activities that regulate inflammation, epigenetics, and other cellular processes. While these energy and signaling mechanisms of ketone bodies are currently being studied in a variety of aging-related diseases such as Alzheimer’s disease and type 2 diabetes mellitus, they may also be relevant to military service members undergoing stressors that mimic or accelerate aging pathways, particularly traumatic brain injury and muscle rehabilitation and recovery. Here we summarize the biology of ketone bodies relevant to resilience and rehabilitation, strategies for translational use of ketone bodies, and current clinical investigations in this area.
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Affiliation(s)
| | - Andrew P Koutnik
- Institute for Human and Machine Cognition, Pensacola, FL, USA.,Department of Molecular Pharmacology and Physiology, USF, Tampa, FL, USA
| | - Jeff S Volek
- Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - John C Newman
- Buck Institute for Research on Aging, Novato, CA, USA. .,Division of Geriatrics, UCSF, San Francisco, CA, USA.
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Kysel P, Haluzíková D, Doležalová RP, Laňková I, Lacinová Z, Kasperová BJ, Trnovská J, Hrádková V, Mráz M, Vilikus Z, Haluzík M. The Influence of Cyclical Ketogenic Reduction Diet vs. Nutritionally Balanced Reduction Diet on Body Composition, Strength, and Endurance Performance in Healthy Young Males: A Randomized Controlled Trial. Nutrients 2020; 12:nu12092832. [PMID: 32947920 PMCID: PMC7551961 DOI: 10.3390/nu12092832] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/14/2022] Open
Abstract
(1) Background: The influence of ketogenic diet on physical fitness remains controversial. We performed a randomized controlled trial to compare the effect of cyclical ketogenic reduction diet (CKD) vs. nutritionally balanced reduction diet (RD) on body composition, muscle strength, and endurance performance. (2) Methods: 25 healthy young males undergoing regular resistance training combined with aerobic training were randomized to CKD (n = 13) or RD (n = 12). Body composition, muscle strength and spiroergometric parameters were measured at baseline and after eight weeks of intervention. (3) Results: Both CKD and RD decreased body weight, body fat, and BMI. Lean body mass and body water decreased in CKD and did not significantly change in RD group. Muscle strength parameters were not affected in CKD while in RD group lat pull-down and leg press values increased. Similarly, endurance performance was not changed in CKD group while in RD group peak workload and peak oxygen uptake increased. (4) Conclusions: Our data show that in healthy young males undergoing resistance and aerobic training comparable weight reduction were achieved by CKD and RD. In RD group; improved muscle strength and endurance performance was noted relative to neutral effect of CKD that also slightly reduced lean body mass.
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Affiliation(s)
- Pavel Kysel
- Department of Sports Medicine, First Faculty of Medicine and General University Hospital, 12000 Prague, Czech Republic; (P.K.); (D.H.); (R.P.D.)
| | - Denisa Haluzíková
- Department of Sports Medicine, First Faculty of Medicine and General University Hospital, 12000 Prague, Czech Republic; (P.K.); (D.H.); (R.P.D.)
| | - Radka Petráková Doležalová
- Department of Sports Medicine, First Faculty of Medicine and General University Hospital, 12000 Prague, Czech Republic; (P.K.); (D.H.); (R.P.D.)
| | - Ivana Laňková
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (I.L.); (Z.L.); (J.T.)
- Diabetes Centre, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (B.J.K.); (V.H.); (M.M.)
| | - Zdeňka Lacinová
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (I.L.); (Z.L.); (J.T.)
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital, 12000 Prague, Czech Republic
| | - Barbora Judita Kasperová
- Diabetes Centre, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (B.J.K.); (V.H.); (M.M.)
| | - Jaroslava Trnovská
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (I.L.); (Z.L.); (J.T.)
| | - Viktorie Hrádková
- Diabetes Centre, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (B.J.K.); (V.H.); (M.M.)
| | - Miloš Mráz
- Diabetes Centre, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (B.J.K.); (V.H.); (M.M.)
| | - Zdeněk Vilikus
- Department of Sports Medicine, First Faculty of Medicine and General University Hospital, 12000 Prague, Czech Republic; (P.K.); (D.H.); (R.P.D.)
- Correspondence: (Z.V.); (M.H.)
| | - Martin Haluzík
- Diabetes Centre, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic; (B.J.K.); (V.H.); (M.M.)
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital, 12000 Prague, Czech Republic
- Correspondence: (Z.V.); (M.H.)
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Murphy NE, Carrigan CT, Margolis LM. High-Fat Ketogenic Diets and Physical Performance: A Systematic Review. Adv Nutr 2020; 12:223-233. [PMID: 32865567 PMCID: PMC7850028 DOI: 10.1093/advances/nmaa101] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/13/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Use of high-fat, ketogenic diets (KDs) to support physical performance has grown in popularity over recent years. While these diets enhance fat and reduce carbohydrate oxidation during exercise, the impact of a KD on physical performance remains controversial. The objective of this work was to assess the effect of KDs on physical performance compared with mixed macronutrient diets [control (CON)]. A systematic review of the literature was conducted using PubMed and Cochrane Library databases. Randomized and nonrandomized studies were included if participants were healthy (free of chronic disease), nonobese [BMI (kg/m2) <30], trained or untrained men or women consuming KD (<50 g carbohydrate/d or serum or whole-blood β-hydroxybutyrate >0.5 mmol/L) compared with CON (fat, 12-38% of total energy intake) diets for ≥14 d, followed by a physical performance test. Seventeen studies (10 parallel, 7 crossover) with 29 performance (13 endurance, 16 power or strength) outcomes were identified. Of the 13 endurance-type performance outcomes, 3 (1 time trial, 2 time-to-exhaustion) reported lower and 10 (4 time trials, 6 time-to-exhaustion) reported no difference in performance between the KD compared with CON. Of the 16 power or strength performance outcomes, 3 (1 power, 2 strength) reported lower, 11 (4 power, 7 strength) no difference, and 2 (power) enhanced performance in the KD compared with the CON. Risk of bias identified some concern of bias primarily due to studies allowing participants to self-select diet intervention groups and the inability to blind participants to the study intervention. Overall, the majority of null results across studies suggest that a KD does not have a positive or negative impact on physical performance compared with a CON diet. However, discordant results between studies may be due to multiple factors, such as the duration consuming study diets, training status, performance test, and sex differences, which will be discussed in this systematic review.
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Affiliation(s)
- Nancy E Murphy
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Christopher T Carrigan
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA
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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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Burke LM, Whitfield J, Heikura IA, Ross MLR, Tee N, Forbes SF, Hall R, McKay AKA, Wallett AM, Sharma AP. Adaptation to a low carbohydrate high fat diet is rapid but impairs endurance exercise metabolism and performance despite enhanced glycogen availability. J Physiol 2020; 599:771-790. [PMID: 32697366 PMCID: PMC7891450 DOI: 10.1113/jp280221] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/14/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Brief (5-6 days) adaptation to a low carbohydrate high fat diet in elite athletes increased exercise fat oxidation to rates previously observed with medium (3-4 weeks) or chronic (>12 months) adherence to this diet, with metabolic changes being washed out in a similar time frame. Increased fat utilisation during exercise was associated with a 5-8% increase in oxygen cost at speeds related to Olympic Programme races. Acute restoration of endogenous carbohydrate (CHO) availability (24 h high CHO diet, pre-race CHO) only partially restored substrate utilisation during a race warm-up. Fat oxidation continued to be elevated above baseline values although it was lower than achieved by 5-6 days' keto adaptation; CHO oxidation only reached 61% and 78% of values previously seen at exercise intensities related to race events. Acute restoration of CHO availability failed to overturn the impairment of high-intensity endurance performance previously associated with low carbohydrate high fat adaptation, potentially due to the blunted capacity for CHO oxidation. ABSTRACT We investigated substrate utilisation during exercise after brief (5-6 days) adaptation to a ketogenic low-carbohydrate (CHO), high-fat (LCHF) diet and similar washout period. Thirteen world-class male race walkers completed economy testing, 25 km training and a 10,000 m race (Baseline), with high CHO availability (HCHO), repeating this (Adaptation) after 5-6 days' LCHF (n = 7; CHO: <50 g day-1 , protein: 2.2 g kg-1 day-1 ; 80% fat) or HCHO (n = 6; CHO: 9.7 g kg-1 day-1 ; protein: 2.2 g kg-1 day-1 ) diet. An Adaptation race was undertaken after 24 h HCHO and pre-race CHO (2 g kg-1 ) diet, identical to the Baseline race. Substantial (>200%) increases in exercise fat oxidation occurred in the LCHF Adaptation economy and 25 km tests, reaching mean rates of ∼1.43 g min-1 . However, relative V ̇ O 2 (ml min-1 kg-1 ) was higher (P < 0.0001), by ∼8% and 5% at speeds related to 50 km and 20 km events. During Adaptation race warm-up in the LCHF group, rates of fat and CHO oxidation at these speeds were decreased and increased, respectively (P < 0.001), compared with the previous day, but were not restored to Baseline values. Performance changes differed between groups (P = 0.009), with all HCHO athletes improving in the Adaptation race (5.7 (5.6)%), while 6/7 LCHF athletes were slower (2.2 (3.4)%). Substrate utilisation returned to Baseline values after 5-6 days of HCHO diet. In summary, robust changes in exercise substrate use occurred in 5-6 days of extreme changes in CHO intake. However, adaptation to a LCHF diet plus acute restoration of endogenous CHO availability failed to restore high-intensity endurance performance, with CHO oxidation rates remaining blunted.
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Affiliation(s)
- Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.,Australian Institute of Sport, Canberra, Australia
| | - Jamie Whitfield
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - Ida A Heikura
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.,Australian Institute of Sport, Canberra, Australia
| | - Megan L R Ross
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.,Australian Institute of Sport, Canberra, Australia
| | - Nicolin Tee
- Australian Institute of Sport, Canberra, Australia
| | | | - Rebecca Hall
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.,Australian Institute of Sport, Canberra, Australia
| | - Alannah K A McKay
- Australian Institute of Sport, Canberra, Australia.,School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, Australia.,Western Australian Institute of Sport, Mt, Claremont, Western Australia, Australia
| | - Alice M Wallett
- Australian Institute of Sport, Canberra, Australia.,University of Canberra Research Institute for Sport and Exercise, Canberra, Australia
| | - Avish P Sharma
- Australian Institute of Sport, Canberra, Australia.,Griffith Sports Physiology and Performance, School of Allied Health Sciences, Griffith University, Southport, Australia
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Intramuscular Mechanisms Mediating Adaptation to Low-Carbohydrate, High-Fat Diets during Exercise Training. Nutrients 2020; 12:nu12092496. [PMID: 32824957 PMCID: PMC7551624 DOI: 10.3390/nu12092496] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/15/2020] [Accepted: 08/17/2020] [Indexed: 12/01/2022] Open
Abstract
Interest in low-carbohydrate, high-fat (LCHF) diets has increased over recent decades given the theorized benefit of associated intramuscular adaptations and shifts in fuel utilization on endurance exercise performance. Consuming a LCHF diet during exercise training increases the availability of fat (i.e., intramuscular triglyceride stores; plasma free fatty acids) and decreases muscle glycogen stores. These changes in substrate availability increase reliance on fat oxidation for energy production while simultaneously decreasing reliance on carbohydrate oxidation for fuel during submaximal exercise. LCHF diet-mediated changes in substrate oxidation remain even after endogenous or exogenous carbohydrate availability is increased, suggesting that the adaptive response driving changes in fat and carbohydrate oxidation lies within the muscle and persists even when the macronutrient content of the diet is altered. This narrative review explores the intramuscular adaptations underlying increases in fat oxidation and decreases in carbohydrate oxidation with LCHF feeding. The possible effects of LCHF diets on protein metabolism and post-exercise muscle remodeling are also considered.
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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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