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Noakes TD. Ketogenic Diets Are Beneficial for Athletic Performance: Response to Burke and Whitfield. Med Sci Sports Exerc 2024; 56:760-762. [PMID: 38079304 DOI: 10.1249/mss.0000000000003345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2024]
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2
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Baart AM, Schaminee H, Mensink M, Terink R. Effect of a low carbohydrate, high fat diet versus a high carbohydrate diet on exercise efficiency and economy in recreational male athletes. J Sports Med Phys Fitness 2023; 63:282-291. [PMID: 36239287 DOI: 10.23736/s0022-4707.22.14066-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Exercise efficiency and economy are key determinants of endurance exercise performance. In this cross-over intervention trial, we investigated the effect of adherence to a low carbohydrate, high fat (LCHF) diet versus a high carbohydrate (HC) diet on gross efficiency (GE) and (OC) during exercise, both after 2 days and after 14 days of adherence. METHODS Fourteen recreational male athletes followed a two-week LCHF diet (<10 energy % carbohydrate) and a two-week HC diet (>50 energy % carbohydrate), in random order, with a wash-out period of three weeks in between. After 2 and 14 days on each diet, the athletes performed a 90-minutes submaximal exercise session on a bicycle ergometer. Indirect calorimetry measurements were done after 60 minutes of exercise to calculate GE and OC. RESULTS GE was significantly lower on the LCHF diet compared to the HC diet, after 2 days (17.6±1.9 vs. 18.8±1.2%, P=0.011, for the LCHF and HC diet respectively), not after 14 days. OC was significantly higher on the LCHF diet compared to the HC diet, after 2 days (1191±138 vs. 1087±72 mL O<inf>2</inf>/kCal, P=0.003, for the LCHF and HC diet respectively), and showed a strong tendency to remain higher after 14 days, P=0.018. CONCLUSIONS Although LCHF diets are popular strategies to increase fat oxidation during exercise, adherence to a LCHF diet was associated with a lower exercise efficiency and economy compared to a HC diet.
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Affiliation(s)
- A Mireille Baart
- Division of Human Nutrition and Health, University of Wageningen, Wageningen, the Netherlands -
| | - Hennes Schaminee
- Division of Human Nutrition and Health, University of Wageningen, Wageningen, the Netherlands
| | - Marco Mensink
- Division of Human Nutrition and Health, University of Wageningen, Wageningen, the Netherlands
| | - Rieneke Terink
- Division of Human Nutrition and Health, University of Wageningen, Wageningen, the Netherlands
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Rothschild JA, Kilding AE, Stewart T, Plews DJ. Factors Influencing Substrate Oxidation During Submaximal Cycling: A Modelling Analysis. Sports Med 2022; 52:2775-2795. [PMID: 35829994 PMCID: PMC9585001 DOI: 10.1007/s40279-022-01727-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Multiple factors influence substrate oxidation during exercise including exercise duration and intensity, sex, and dietary intake before and during exercise. However, the relative influence and interaction between these factors is unclear. OBJECTIVES Our aim was to investigate factors influencing the respiratory exchange ratio (RER) during continuous exercise and formulate multivariable regression models to determine which factors best explain RER during exercise, as well as their relative influence. METHODS Data were extracted from 434 studies reporting RER during continuous cycling exercise. General linear mixed-effect models were used to determine relationships between RER and factors purported to influence RER (e.g., exercise duration and intensity, muscle glycogen, dietary intake, age, and sex), and to examine which factors influenced RER, with standardized coefficients used to assess their relative influence. RESULTS The RER decreases with exercise duration, dietary fat intake, age, VO2max, and percentage of type I muscle fibers, and increases with dietary carbohydrate intake, exercise intensity, male sex, and carbohydrate intake before and during exercise. The modelling could explain up to 59% of the variation in RER, and a model using exclusively easily modified factors (exercise duration and intensity, and dietary intake before and during exercise) could only explain 36% of the variation in RER. Variables with the largest effect on RER were sex, dietary intake, and exercise duration. Among the diet-related factors, daily fat and carbohydrate intake have a larger influence than carbohydrate ingestion during exercise. CONCLUSION Variability in RER during exercise cannot be fully accounted for by models incorporating a range of participant, diet, exercise, and physiological characteristics. To better understand what influences substrate oxidation during exercise further research is required on older subjects and females, and on other factors that could explain additional variability in RER.
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Affiliation(s)
- Jeffrey A Rothschild
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Tom Stewart
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Abstract
Obesity remains a serious relevant public health concern throughout the world despite related countermeasures being well understood (i.e. mainly physical activity and an adjusted diet). Among different nutritional approaches, there is a growing interest in ketogenic diets (KD) to manipulate body mass (BM) and to enhance fat mass loss. KD reduce the daily amount of carbohydrate intake drastically. This results in increased fatty acid utilisation, leading to an increase in blood ketone bodies (acetoacetate, 3-β-hydroxybutyrate and acetone) and therefore metabolic ketosis. For many years, nutritional intervention studies have focused on reducing dietary fat with little or conflicting positive results over the long term. Moreover, current nutritional guidelines for athletes propose carbohydrate-based diets to augment muscular adaptations. This review discusses the physiological basis of KD and their effects on BM reduction and body composition improvements in sedentary individuals combined with different types of exercise (resistance training or endurance training) in individuals with obesity and athletes. Ultimately, we discuss the strengths and the weaknesses of these nutritional interventions together with precautionary measures that should be observed in both individuals with obesity and athletic populations. A literature search from 1921 to April 2021 using Medline, Google Scholar, PubMed, Web of Science, Scopus and Sportdiscus Databases was used to identify relevant studies. In summary, based on the current evidence, KD are an efficient method to reduce BM and body fat in both individuals with obesity and athletes. However, these positive impacts are mainly because of the appetite suppressive effects of KD, which can decrease daily energy intake. Therefore, KD do not have any superior benefits to non-KD in BM and body fat loss in individuals with obesity and athletic populations in an isoenergetic situation. In sedentary individuals with obesity, it seems that fat-free mass (FFM) changes appear to be as great, if not greater, than decreases following a low-fat diet. In terms of lean mass, it seems that following a KD can cause FFM loss in resistance-trained individuals. In contrast, the FFM-preserving effects of KD are more efficient in endurance-trained compared with resistance-trained individuals.
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Noakes TD. What Is the Evidence That Dietary Macronutrient Composition Influences Exercise Performance? A Narrative Review. Nutrients 2022; 14:862. [PMID: 35215511 PMCID: PMC8875928 DOI: 10.3390/nu14040862] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 01/06/2023] Open
Abstract
The introduction of the needle muscle biopsy technique in the 1960s allowed muscle tissue to be sampled from exercising humans for the first time. The finding that muscle glycogen content reached low levels at exhaustion suggested that the metabolic cause of fatigue during prolonged exercise had been discovered. A special pre-exercise diet that maximized pre-exercise muscle glycogen storage also increased time to fatigue during prolonged exercise. The logical conclusion was that the athlete's pre-exercise muscle glycogen content is the single most important acutely modifiable determinant of endurance capacity. Muscle biochemists proposed that skeletal muscle has an obligatory dependence on high rates of muscle glycogen/carbohydrate oxidation, especially during high intensity or prolonged exercise. Without this obligatory carbohydrate oxidation from muscle glycogen, optimum muscle metabolism cannot be sustained; fatigue develops and exercise performance is impaired. As plausible as this explanation may appear, it has never been proven. Here, I propose an alternate explanation. All the original studies overlooked one crucial finding, specifically that not only were muscle glycogen concentrations low at exhaustion in all trials, but hypoglycemia was also always present. Here, I provide the historical and modern evidence showing that the blood glucose concentration-reflecting the liver glycogen rather than the muscle glycogen content-is the homeostatically-regulated (protected) variable that drives the metabolic response to prolonged exercise. If this is so, nutritional interventions that enhance exercise performance, especially during prolonged exercise, will be those that assist the body in its efforts to maintain the blood glucose concentration within the normal range.
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Affiliation(s)
- Timothy David Noakes
- Department of Applied Design, Cape Peninsula University of Technology, Cape Town 8000, South Africa
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6
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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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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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8
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Marchant ED, Marchant ND, Hyldahl RD, Gifford JR, Smith MW, Hancock CR. Skeletal Muscle Mitochondrial Function after a 100-km Ultramarathon: A Case Study in Monozygotic Twins. Med Sci Sports Exerc 2021; 53:2363-2373. [PMID: 34107508 DOI: 10.1249/mss.0000000000002715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Very little research has investigated the effects of ultraendurance exercise on the bioenergetic status of muscle. The primary objective of this case study was to characterize the changes that occur in skeletal muscle mitochondria in response to a 100-km ultramarathon in monozygotic twins. A second objective was to determine whether mitochondrial function is altered by consuming a periodized low-carbohydrate, high-fat diet during training compared with a high-carbohydrate diet. METHODS One pair of male monozygotic twins ran 100 km on treadmills after 4 wk of training on either a high-carbohydrate or periodized low-carbohydrate, high-fat diet. Muscle biopsies were collected 4 wk before the run, as well as 4 and 52 h postrun. Blood draws were also performed immediately before as well as 4 and 52 h after the run. RESULTS Four hours postrun, respiratory capacity, citrate synthase activity, and mitochondrial complex protein content were decreased. Two days later, both twins showed signs of rapid recovery in several of these measures. Furthermore, blood levels of creatine phosphokinase, C-reactive protein, and aspartate transaminase were elevated 4 h after the run but partially recovered 2 d later. CONCLUSION Although there were some differences between the twins, the primary finding is that there is significant mitochondrial impairment induced by running 100 km, which rapidly recovers within 2 d. These results provide ample rationale for future investigations of the effects of ultraendurance activity on mitochondrial function.
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Affiliation(s)
- Erik D Marchant
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| | - Nathan D Marchant
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| | | | | | - Michael W Smith
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| | - Chad R Hancock
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
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9
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Ratia N, Pietiläinen KH, Auranen M, Saksa L, Luukkonen R, Suomalainen A, Piirilä P. Modified Atkins diet modifies cardiopulmonary exercise characteristics and promotes hyperventilation in healthy subjects. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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10
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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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11
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Effects of a Short-Term "Fat Adaptation with Carbohydrate Restoration" Diet on Metabolic Responses and Exercise Performance in Well-Trained Runners. Nutrients 2021; 13:nu13031033. [PMID: 33806822 PMCID: PMC8005046 DOI: 10.3390/nu13031033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Periodized carbohydrate availability can enhance exercise capacity, but the effects of short-term fat adaptation carbohydrate restoration (FACR) diets on metabolic responses and exercise performance in endurance athletes have not been conclusively determined. This study aimed to investigate the effect of a FACR diet on measures of resting metabolism, exercise metabolism, and exercise performance. Well-trained male runners (n = 8) completed a FACR dietary intervention (five days' carbohydrate < 20% and fat > 60% energy, plus one-day carbohydrate ≥ 70% energy), and a control high-carbohydrate (HCHO) diet for six days (carbohydrate > 60% energy; fat < 20% energy) in a randomized crossover design. Pre- and post-intervention metabolic measures included resting metabolic rate (RMR), respiratory quotient (RQ), maximum fat oxidation rate during exercise (MFO), and maximum fat oxidation intensity (FATmax). Measures of exercise performance included maximal oxygen uptake (VO2max), running economy (RE), and 5 km running time trial (5 km-TT). In FACR compared with HCHO, there were significant improvements in FATmax (p = 0.006) and RE (p = 0.048). There were no significant differences (p > 0.05) between FACR and HCHO in RMR, RQ, VO2max, or 5 km-TT. Findings suggest that a short-term (six days) FACR diet may facilitate increased fat oxidation and submaximal exercise economy but does not improve 5 km-TT performance.
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12
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Devrim-Lanpir A, Hill L, Knechtle B. Efficacy of Popular Diets Applied by Endurance Athletes on Sports Performance: Beneficial or Detrimental? A Narrative Review. Nutrients 2021; 13:nu13020491. [PMID: 33540813 PMCID: PMC7912997 DOI: 10.3390/nu13020491] [Citation(s) in RCA: 21] [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: 12/11/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Endurance athletes need a regular and well-detailed nutrition program in order to fill their energy stores before training/racing, to provide nutritional support that will allow them to endure the harsh conditions during training/race, and to provide effective recovery after training/racing. Since exercise-related gastrointestinal symptoms can significantly affect performance, they also need to develop strategies to address these issues. All these factors force endurance athletes to constantly seek a better nutritional strategy. Therefore, several new dietary approaches have gained interest among endurance athletes in recent decades. This review provides a current perspective to five popular diet approaches: (a) vegetarian diets, (b) high-fat diets, (c) intermittent fasting diets, (d) gluten-free diet, and (e) low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diets. We reviewed scientific studies published from 1983 to January 2021 investigating the impact of these popular diets on the endurance performance and health aspects of endurance athletes. We also discuss all the beneficial and harmful aspects of these diets, and offer key suggestions for endurance athletes to consider when following these diets.
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Affiliation(s)
- Aslı Devrim-Lanpir
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Istanbul Medeniyet University, 34862 Istanbul, Turkey;
| | - Lee Hill
- Division of Gastroenterology & Nutrition, Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada;
| | - Beat Knechtle
- Medbase St. Gallen, am Vadianplatz, 9001 St. Gallen, Switzerland
- Institute of Primary Care, University of Zurich, 8091 Zurich, Switzerland
- Correspondence: ; Tel.: +41-(0)-71-226-93-00
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13
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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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14
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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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Dos Santos Quaresma MVL, Guazzelli Marques C, Nakamoto FP. Effects of diet interventions, dietary supplements, and performance-enhancing substances on the performance of CrossFit-trained individuals: A systematic review of clinical studies. Nutrition 2020; 82:110994. [PMID: 33051114 DOI: 10.1016/j.nut.2020.110994] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/03/2020] [Accepted: 08/08/2020] [Indexed: 12/14/2022]
Abstract
CrossFit (CF) is characterized as a constantly varied, high-intensity, functional movement training program, performed with little or no rest between bouts, combining strength and endurance exercises, such as running, cycling, rowing, Olympic weightlifting, power weightlifting, and gymnastic-type exercises. Several nutritional strategies are used to improve sports performance of CF practitioners; however, most of them are empirical and lack scientific evidence. Thus, the aim of this review was to determine the effects of diet intervention, dietary supplements, and performance-enhancing substances on exercise-performance parameters of CF practitioners. MEDLINE/PubMed, Web of Science, LILACS, SciELO, and Scopus databases were searched using specific Medical Subject Headings and keywords for clinical studies that enrolled CF athletes in an intervention using diet, dietary supplements, or performance-enhancing substances. Athletic performance was considered as the primary outcome. No other filters were applied. Including grey literature search, 219 studies were identified; however only 14 studies met the eligibility criteria. Two studies evaluated the effects of caffeine supplementation on exercise performance; five studies evaluated high- or low-carbohydrate effects on performance and other parameters. One study verified the effects of multi-ingredient supplementation on CF-specific performance and body composition. One study compared the intake of protein supplements on performance and body composition. Two studies assessed the effect of green tea and (-)-epicatechin on performance and other parameters. One study evaluated the effects of nitrate supplementation on exercise performance. One study investigated the effect of betaine supplementation on body composition and muscle performance. Finally, one study examined the effects of sodium bicarbonate (SB) ingestion on exercise performance and aerobic capacity. Only SB supplementation improved CF performance. These outcomes may have been obtained due to methodological limitations such as small sample size, lack of control over influencing variables, short period of exercise intervention. Despite the popularity and growing evidence about CF, little is known about the relationship between performance-enhancing substances or dietary interventions and CF performance. Given the lack of scientific evidence, new studies with potential ergogenic supplements, a better methodological model, and practical application are required.
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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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17
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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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18
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Burke LM, Sharma AP, Heikura IA, Forbes SF, Holloway M, McKay AKA, Bone JL, Leckey JJ, Welvaert M, Ross ML. Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic low carbohydrate, high fat (LCHF) diet is reproducible. PLoS One 2020; 15:e0234027. [PMID: 32497061 PMCID: PMC7272074 DOI: 10.1371/journal.pone.0234027] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 05/15/2020] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION We repeated our study of intensified training on a ketogenic low-carbohydrate (CHO), high-fat diet (LCHF) in world-class endurance athletes, with further investigation of a "carryover" effect on performance after restoring CHO availability in comparison to high or periodised CHO diets. METHODS After Baseline testing (10,000 m IAAF-sanctioned race, aerobic capacity and submaximal walking economy) elite male and female race walkers undertook 25 d supervised training and repeat testing (Adapt) on energy-matched diets: High CHO availability (8.6 g∙kg-1∙d-1 CHO, 2.1 g∙kg-1∙d-1 protein; 1.2 g∙kg-1∙d-1 fat) including CHO before/during/after workouts (HCHO, n = 8): similar macronutrient intake periodised within/between days to manipulate low and high CHO availability at various workouts (PCHO, n = 8); and LCHF (<50 g∙d-1 CHO; 78% energy as fat; 2.1 g∙kg-1∙d-1 protein; n = 10). After Adapt, all athletes resumed HCHO for 2.5 wk before a cohort (n = 19) completed a 20 km race. RESULTS All groups increased VO2peak (ml∙kg-1∙min-1) at Adapt (p = 0.02, 95%CI: [0.35-2.74]). LCHF markedly increased whole-body fat oxidation (from 0.6 g∙min-1 to 1.3 g∙min-1), but also the oxygen cost of walking at race-relevant velocities. Differences in 10,000 m performance were clear and meaningful: HCHO improved by 4.8% or 134 s (95% CI: [207 to 62 s]; p < 0.001), with a trend for a faster time (2.2%, 61 s [-18 to +144 s]; p = 0.09) in PCHO. LCHF were slower by 2.3%, -86 s ([-18 to -144 s]; p < 0.001), with no evidence of superior "rebound" performance over 20 km after 2.5 wk of HCHO restoration and taper. CONCLUSION Our previous findings of impaired exercise economy and performance of sustained high-intensity race walking following keto-adaptation in elite competitors were repeated. Furthermore, there was no detectable benefit from undertaking an LCHF intervention as a periodised strategy before a 2.5-wk race preparation/taper with high CHO availability. TRIAL REGISTRATION Australia New Zealand Clinical Trial Registry: ACTRN12619000794101.
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Affiliation(s)
- Louise M. Burke
- Australian Institute of Sport, Canberra, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - Avish P. Sharma
- Australian Institute of Sport, Canberra, Australia
- Griffith Sports Physiology and Performance, School of Allied Health Sciences, Griffith University, Gold Coast, Australia
| | - Ida A. Heikura
- Australian Institute of Sport, Canberra, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | | | | | - Alannah K. A. McKay
- Australian Institute of Sport, Canberra, Australia
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, WA, Australia
- Western Australian Institute of Sport, Mt Claremont, WA, Australia
| | - Julia L. Bone
- Australian Institute of Sport, Canberra, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - Jill J. Leckey
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - Marijke Welvaert
- Australian Institute of Sport, Canberra, Australia
- University of Canberra Research Institute for Sport and Exercise, Canberra, Australia
| | - Megan L. Ross
- Australian Institute of Sport, Canberra, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
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19
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Waldman HS, Smith JW, Lamberth J, Fountain BJ, McAllister MJ. A 28-Day Carbohydrate-Restricted Diet Improves Markers of Cardiometabolic Health and Performance in Professional Firefighters. J Strength Cond Res 2020; 33:3284-3294. [PMID: 31469768 DOI: 10.1519/jsc.0000000000003354] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Waldman, HS, Smith, JW, Lamberth, J, Fountain, BJ, and McAllister, MJ. A 28-day carbohydrate-restricted diet improves markers of cardiometabolic health and performance in professional firefighters. J Strength Cond Res 33(12): 3284-3294, 2019-We investigated the effects of a 4-week ad-libitum, nonketogenic, carbohydrate-restricted (<25% of calories) diet (CRD) on cardiometabolic and performance markers in firefighters (FF). Subjects (n = 15) completed 9 sessions (trials 1-3 [familiarization], trials 4-6 [baseline], and trials 7-9 [post-CRD]). Following habitual western diet, anthropometric measures were assessed, glucose tolerance measured, and then completed a graded cycling test, maximal Wingate test, and conducted their FF physical performance assessment (FPPA) to measure performance while metabolic variables and perceptual responses were recorded. Subjects then adhered to a CRD for a 4-week duration and returned for repeat testing. Body fat as measured by BodPod, and 7-site skinfold thickness decreased (p < 0.01), and a decrease was observed in blood pressure (BP) (p < 0.01; ∼5 mm Hg) after CRD. There were no differences found for glucose tolerance, but an increase was found for fat oxidation rates (p < 0.01; ∼0.07 g·min) and a decrease in carbohydrate oxidation rates across a range of intensities (p < 0.01; ∼0.24 g·min). Finally, the 2.41-km run and pull-up performance during the FPPA improved (p < 0.01; ∼41 second and 3 repetitions, respectively) and with no differences observed between treatments regarding the Wingate test. To date, this is the first CRD implemented with FF and resulted in decreased fat mass (∼2.4 kg), BP, and improvements to performance on the FPPA while preserving high-intensity exercise. These data suggest that a 28-day CRD can benefit markers of health in professional FF without detriments to occupational performance.
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Affiliation(s)
- Hunter S Waldman
- Human Performance Lab, Department of Kinesiology, University of North Alabama, Florence, Alabama.,Applied Physiology Lab, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - JohnEric W Smith
- Applied Physiology Lab, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - John Lamberth
- Applied Physiology Lab, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - Brent J Fountain
- Department of Food Science, Nutrition, and Health Promotion, Mississippi State University, Starkville, Mississippi
| | - Matthew J McAllister
- Metabolic and Applied Physiology Lab, Department of Health and Human Performance, Texas State University, San Marcos, Texas
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20
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Valsdottir TD, Henriksen C, Odden N, Nellemann B, Jeppesen PB, Hisdal J, Westerberg AC, Jensen J. Effect of a Low-Carbohydrate High-Fat Diet and a Single Bout of Exercise on Glucose Tolerance, Lipid Profile and Endothelial Function in Normal Weight Young Healthy Females. Front Physiol 2019; 10:1499. [PMID: 31920704 PMCID: PMC6931312 DOI: 10.3389/fphys.2019.01499] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/25/2019] [Indexed: 01/07/2023] Open
Abstract
Low-carbohydrate-high-fat (LCHF) diets are efficient for weight loss, and are also used by healthy people to maintain bodyweight. The main aim of this study was to investigate the effect of 3-week energy-balanced LCHF-diet, with >75 percentage energy (E%) from fat, on glucose tolerance and lipid profile in normal weight, young, healthy women. The second aim of the study was to investigate if a bout of exercise would prevent any negative effect of LCHF-diet on glucose tolerance. Seventeen females participated, age 23.5 ± 0.5 years; body mass index 21.0 ± 0.4 kg/m2, with a mean dietary intake of 78 ± 1 E% fat, 19 ± 1 E% protein and 3 ± 0 E% carbohydrates. Measurements were performed at baseline and post-intervention. Fasting glucose decreased from 4.7 ± 0.1 to 4.4 mmol/L (p < 0.001) during the dietary intervention whereas fasting insulin was unaffected. Glucose area under the curve (AUC) and insulin AUC did not change during an OGTT after the intervention. Before the intervention, a bout of aerobic exercise reduced fasting glucose (4.4 ± 0.1 mmol/L, p < 0.001) and glucose AUC (739 ± 41 to 661 ± 25, p = 0.008) during OGTT the following morning. After the intervention, exercise did not reduce fasting glucose the following morning, and glucose AUC during an OGTT increased compared to the day before (789 ± 43 to 889 ± 40 mmol/L∙120min–1, p = 0.001). AUC for insulin was unaffected. The dietary intervention increased total cholesterol (p < 0.001), low-density lipoprotein (p ≤ 0.001), high-density lipoprotein (p = 0.011), triglycerides (p = 0.035), and free fatty acids (p = 0.021). In conclusion, 3-week LCHF-diet reduced fasting glucose, while glucose tolerance was unaffected. A bout of exercise post-intervention did not decrease AUC glucose as it did at baseline. Total cholesterol increased, mainly due to increments in low-density lipoprotein. LCHF-diets should be further evaluated and carefully considered for healthy individuals.
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Affiliation(s)
- Thorhildur Ditta Valsdottir
- Department of Medicine, Atlantis Medical University College, Oslo, Norway.,Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Christine Henriksen
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Nancy Odden
- Department of Nutrition, Atlantis Medical University College, Oslo, Norway
| | - Birgitte Nellemann
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Per B Jeppesen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jonny Hisdal
- Oslo Vascular Center, Department of Vascular Surgery, Oslo University Hospital, Oslo, Norway
| | - Ane C Westerberg
- Department of Nutrition, Atlantis Medical University College, Oslo, Norway.,Institute of Health Sciences, Kristiania University College, Oslo, Norway
| | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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21
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Abstract
Over the last decade, in support of training periodization, there has been an emergence around the concept of nutritional periodization. Within athletics (track and field), the science and art of periodization is a cornerstone concept with recent commentaries emphasizing the underappreciated complexity associated with predictable performance on demand. Nevertheless, with varying levels of evidence, sport and event specific sequencing of various training units and sessions (long [macrocycle; months], medium [mesocycle; weeks], and short [microcycle; days and within-day duration]) is a routine approach to training periodization. Indeed, implementation of strategic temporal nutrition interventions (macro, meso, and micro) can support and enhance training prescription and adaptation, as well as acute event specific performance. However, a general framework on how, why, and when nutritional periodization could be implemented has not yet been established. It is beyond the scope of this review to highlight every potential nutritional periodization application. Instead, this review will focus on a generalized framework, with specific examples of macro-, meso-, and microperiodization for the macronutrients of carbohydrates, and, by extension, fat. More specifically, the authors establish the evidence and rationale for situations of acute high carbohydrate availability, as well as the evidence for more chronic manipulation of carbohydrates coupled with training. The topic of periodized nutrition has made considerable gains over the last decade but is ripe for further scientific progress and field application.
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22
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Waldman HS, Krings BM, Basham SA, Smith JEW, Fountain BJ, McAllister MJ. Effects of a 15-Day Low Carbohydrate, High-Fat Diet in Resistance-Trained Men. J Strength Cond Res 2019; 32:3103-3111. [PMID: 29076962 DOI: 10.1519/jsc.0000000000002282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Waldman, HS, Krings, BM, Basham, SA, Smith, JW, Fountain, BJ, and McAllister, MJ. Effects of a 15-day low carbohydrate, high-fat diet in resistance-trained men. J Strength Cond Res 32(11): 3103-3111, 2018-This study examined the effects of a 15-day isocaloric low carbohydrate (<25% E), high-fat (>50% E) (LCHF) diet on physiological and metabolic alterations in resistance-trained (RT) men. College-aged RT men (n = 11) completed 4 V[Combining Dot Above]O2max tests using treadmill every 5 days during the 15-day trial. Blood was drawn intravenously pre-exercise across each experimental trial for insulin, cortisol, and glucose. Pulmonary data were collected and substrate oxidation (OXI) was calculated during exercise. Body mass decreased (p < 0.04) with no further changes in anthropometric measures. Time to exhaustion was not affected across each day. Insulin dropped below baseline values (p < 0.0005). Cortisol increased from baseline to day 5 (p < 0.004) but returned back to near baseline at day 10, whereas glucose remained within normal range throughout the duration of the study. Carbohydrate (CHO) OXI dropped (p < 0.001) from baseline to day 5, and fat OXI increased from baseline to day 5 (p < 0.0001). Heart rate decreased from baseline to day 5 (p < 0.001) and again from day 10 to 15 (p < 0.02). Oxygen uptake (V[Combining Dot Above]O2) decreased from day 5 to 10 (p < 0.0001). A nonketo LCHF diet appears to favor RT men by altering metabolic markers without decrements in aerobic performance and be a potential diet intervention used by coaches. However, the reported cardiorespiratory responses should be interpreted reasonably because of the possibility the subjects running economy improved over experimental trials.
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Affiliation(s)
- Hunter S Waldman
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - Ben M Krings
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - Steven A Basham
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - John Eric W Smith
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
| | - Brent J Fountain
- Department of Food Science, Nutrition, and Health Promotion, Mississippi State University, Starkville, Mississippi
| | - Matthew J McAllister
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Starkville, Mississippi
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23
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Burckhardt MA, Chetty T, Smith GJ, Adolfsson P, de Bock M, Jones TW, Davis EA. Use of Continuous Glucose Monitoring Trends to Facilitate Exercise in Children with Type 1 Diabetes. Diabetes Technol Ther 2019; 21:51-55. [PMID: 30620642 DOI: 10.1089/dia.2018.0292] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Diabetes care during exercise frequently requires interruptions to activity and adds extra challenges particularly for young individuals with type 1 diabetes (T1D). This study investigated the use of a carbohydrate (CHO) intake algorithm based on continuous glucose monitoring (CGM) trends during physical activity. Children with T1D diagnosed for >1 year, ages 8-12 years, with a glycated hemoglobin of <10% were recruited into a randomized crossover study. They attended two similar mornings of fun-based physical activity and adhered to either a CHO intake algorithm based on CGM trends (intervention) or to standard exercise guidelines (consumption of 0.5 g CHO/kg/h when glucose <8 mmol/L) (control). Outcome measures included events such as exercise interruptions, CHO intake, and hypoglycemia events and percentage time spent in different sensor glucose ranges. Fourteen children completed the study. No episodes of significant hypoglycemia (sensor glucose level <3.0 mmol/L) occurred in either arm. Mean CHO intake was the same in both arms, 0.3 ± 0.2 g/kg/h. However, the intervention algorithm resulted in fewer CHO intake events per day: rate [95% confidence interval] 2.4 [1.6-2.3] versus 0.9 [0.4-1.5], P < 0.001, and exercise interruptions: 7.2 [5.9-8.8] versus 1.4 [0.8-2.1], P < 0.001, compared with control. There was no evidence of a difference in percentage time in range (3.9-10 mmol/L) and percentage time spent high between study arms. Both control and intervention protocols prevented significant hypoglycemia. Using a CHO intake algorithm based on CGM trends resulted in fewer CHO intake events and fewer interruptions to exercise. Use of this algorithm may reduce the burden of diabetes management with potential to facilitate activity in young people with T1D.
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Affiliation(s)
- Marie-Anne Burckhardt
- 1 Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- 2 Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia
- 3 Division of Paediatrics, within the Medical School, The University of Western Australia, Perth, Australia
| | - Tarini Chetty
- 1 Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- 2 Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia
| | - Grant J Smith
- 1 Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Peter Adolfsson
- 4 Department of Paediatrics, The hospital of Halland, Kungsbacka, Sweden
- 5 Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Martin de Bock
- 1 Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- 2 Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia
| | - Timothy W Jones
- 1 Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- 2 Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia
- 3 Division of Paediatrics, within the Medical School, The University of Western Australia, Perth, Australia
| | - Elizabeth A Davis
- 1 Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- 2 Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia
- 3 Division of Paediatrics, within the Medical School, The University of Western Australia, Perth, Australia
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24
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Chetty T, Shetty V, Fournier PA, Adolfsson P, Jones TW, Davis EA. Exercise Management for Young People With Type 1 Diabetes: A Structured Approach to the Exercise Consultation. Front Endocrinol (Lausanne) 2019; 10:326. [PMID: 31258513 PMCID: PMC6587067 DOI: 10.3389/fendo.2019.00326] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 05/07/2019] [Indexed: 12/11/2022] Open
Abstract
Regular physical activity during childhood is important for optimal physical and psychological development. For individuals with Type 1 Diabetes (T1D), physical activity offers many health benefits including improved glycemic control, cardiovascular function, blood lipid profiles, and psychological well-being. Despite these benefits, many young people with T1D do not meet physical activity recommendations. Barriers to engaging in a physically active lifestyle include fear of hypoglycemia, as well as insufficient knowledge in managing diabetes around exercise in both individuals and health care professionals. Diabetes and exercise management is complex, and many factors can influence an individual's glycemic response to exercise including exercise related factors (such as type, intensity and duration of the activity) and person specific factors (amount of insulin on board, person's stress/anxiety and fitness levels). International guidelines provide recommendations for clinical practice, however a gap remains in how to apply these guidelines to a pediatric exercise consultation. Consequently, it can be challenging for health care practitioners to advise young people with T1D how to approach exercise management in a busy clinic setting. This review provides a structured approach to the child/adolescent exercise consultation, based on a framework of questions, to assist the health care professional in formulating person-specific exercise management plans for young people with T1D.
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Affiliation(s)
- Tarini Chetty
- Children's Diabetes Centre, Perth Children's Hospital, Perth, WA, Australia
- *Correspondence: Tarini Chetty
| | - Vinutha Shetty
- Children's Diabetes Centre, Perth Children's Hospital, Perth, WA, Australia
- UWA Centre for Child Health Research, University of Western Australia, Perth, WA, Australia
| | - Paul Albert Fournier
- School of Human Sciences, University of Western Australia, Perth, WA, Australia
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
| | - Peter Adolfsson
- Department of Pediatrics, The Hospital of Halland, Kungsbacka, Sweden
- Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Timothy William Jones
- Children's Diabetes Centre, Perth Children's Hospital, Perth, WA, Australia
- UWA Centre for Child Health Research, University of Western Australia, Perth, WA, Australia
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
| | - Elizabeth Ann Davis
- Children's Diabetes Centre, Perth Children's Hospital, Perth, WA, Australia
- UWA Centre for Child Health Research, University of Western Australia, Perth, WA, Australia
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
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25
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Nikolaidis PT, Veniamakis E, Rosemann T, Knechtle B. Nutrition in Ultra-Endurance: State of the Art. Nutrients 2018; 10:nu10121995. [PMID: 30558350 PMCID: PMC6315825 DOI: 10.3390/nu10121995] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/02/2018] [Accepted: 12/11/2018] [Indexed: 11/18/2022] Open
Abstract
Athletes competing in ultra-endurance sports should manage nutritional issues, especially with regards to energy and fluid balance. An ultra-endurance race, considered a duration of at least 6 h, might induce the energy balance (i.e., energy deficit) in levels that could reach up to ~7000 kcal per day. Such a negative energy balance is a major health and performance concern as it leads to a decrease of both fat and skeletal muscle mass in events such as 24-h swimming, 6-day cycling or 17-day running. Sport anemia caused by heavy exercise and gastrointestinal discomfort, under hot or cold environmental conditions also needs to be considered as a major factor for health and performance in ultra-endurance sports. In addition, fluid losses from sweat can reach up to 2 L/h due to increased metabolic work during prolonged exercise and exercise under hot environments that might result in hypohydration. Athletes are at an increased risk for exercise-associated hyponatremia (EAH) and limb swelling when intake of fluids is greater than the volume lost. Optimal pre-race nutritional strategies should aim to increase fat utilization during exercise, and the consumption of fat-rich foods may be considered during the race, as well as carbohydrates, electrolytes, and fluid. Moreover, to reduce the risk of EAH, fluid intake should include sodium in the amounts of 10–25 mmol to reduce the risk of EAH and should be limited to 300–600 mL per hour of the race.
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Affiliation(s)
- Pantelis T Nikolaidis
- Laboratory of Exercise Testing, Hellenic Air Force Academy, 13671 Dekelia, Greece.
- Exercise Physiology Laboratory, 18450 Nikaia, Greece.
| | - Eleftherios Veniamakis
- Department of Nutrition and Dietetics, Technological Educational Institute, 72300 Sitia, Greece.
| | - Thomas Rosemann
- Institute of General Practice and for Health Services Research, University of Zurich, 8091 Zurich, Switzerland.
| | - Beat Knechtle
- Institute of General Practice and for Health Services Research, University of Zurich, 8091 Zurich, Switzerland.
- Medbase St. Gallen Am Vadianplatz, 9001 St. Gallen, Switzerland.
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26
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Abstract
The exploits of elite athletes delight, frustrate, and confound us as they strive to reach their physiological, psychological, and biomechanical limits. We dissect nutritional approaches to optimal performance, showcasing the contribution of modern sports science to gold medals and world titles. Despite an enduring belief in a single, superior “athletic diet,” diversity in sports nutrition practices among successful athletes arises from the specificity of the metabolic demands of different sports and the periodization of training and competition goals. Pragmatic implementation of nutrition strategies in real-world scenarios and the prioritization of important strategies when nutrition themes are in conflict add to this variation. Lastly, differences in athlete practices both promote and reflect areas of controversy and disagreement among sports nutrition experts.
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27
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Earnest CP, Rothschild J, Harnish CR, Naderi A. Metabolic adaptations to endurance training and nutrition strategies influencing performance. Res Sports Med 2018; 27:134-146. [PMID: 30411978 DOI: 10.1080/15438627.2018.1544134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Endurance performance is the result of optimal training targeting cardiovascular, metabolic, and peripheral muscular adaptations and is coupled to effective nutrition strategies via the use of macronutrient manipulations surrounding training and potential supplementation with ergogenic aids. It is important to note that training and nutrition may differ according to the individual needs of the athlete and can markedly impact the physiological response to training. Herein, we discuss various aspects of endurance training adaptations, nutritional strategies and their contributions to towards performance.
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Affiliation(s)
- Conrad P Earnest
- a Health and Kinesiology, College Station , Texas A&M University , College Station , TX , USA
| | | | | | - Alireza Naderi
- d Department of Sport Physiology , Islamic Azad University , Boroujerd , Iran (the Islamic Republic of)
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28
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Toward a Common Understanding of Diet-Exercise Strategies to Manipulate Fuel Availability for Training and Competition Preparation in Endurance Sport. Int J Sport Nutr Exerc Metab 2018; 28:451-463. [PMID: 30249148 DOI: 10.1123/ijsnem.2018-0289] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
From the breakthrough studies of dietary carbohydrate and exercise capacity in the 1960s through to the more recent studies of cellular signaling and the adaptive response to exercise in muscle, it has become apparent that manipulations of dietary fat and carbohydrate within training phases, or in the immediate preparation for competition, can profoundly alter the availability and utilization of these major fuels and, subsequently, the performance of endurance sport (events >30 min up to ∼24 hr). A variety of terms have emerged to describe new or nuanced versions of such exercise-diet strategies (e.g., train low, train high, low-carbohydrate high-fat diet, periodized carbohydrate diet). However, the nonuniform meanings of these terms have caused confusion and miscommunication, both in the popular press and among the scientific community. Sports scientists will continue to hold different views on optimal protocols of fuel support for training and competition in different endurance events. However, to promote collaboration and shared discussions, a commonly accepted and consistent terminology will help to strengthen hypotheses and experimental/experiential data around various strategies. We propose a series of definitions and explanations as a starting point for a more unified dialogue around acute and chronic manipulations of fat and carbohydrate in the athlete's diet, noting philosophies of approaches rather than a single/definitive macronutrient prescription. We also summarize some of the key questions that need to be tackled to help produce greater insight into this exciting area of sports nutrition research and practice.
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29
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Rothschild J, Earnest CP. Dietary Manipulations Concurrent to Endurance Training. J Funct Morphol Kinesiol 2018; 3:jfmk3030041. [PMID: 33466970 PMCID: PMC7739303 DOI: 10.3390/jfmk3030041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/11/2018] [Accepted: 07/23/2018] [Indexed: 12/20/2022] Open
Abstract
The role of an athlete's dietary intake (both timing and food type) goes beyond simply providing fuel to support the body's vital processes. Nutritional choices also have an impact on the metabolic adaptations to training. Over the past 20 years, research has suggested that strategically reducing carbohydrate (CHO) availability during an athlete's training can modify the metabolic responses in lieu of simply maintaining a high CHO diet. Several methods have been explored to manipulate CHO availability and include: Low-carb, high-fat (LCHF) diets, performing two-a-day training without glycogen restoration between sessions, and a "sleep-low" approach entailing a glycogen-depleting session in the evening without consuming CHO until after a morning training session performed in an overnight fasted state. Each of these methods can confer beneficial metabolic adaptations for the endurance athlete including increases in mitochondrial enzyme activity, mitochondrial content, and rates of fat oxidation, yet data showing a direct performance benefit is still unclear.
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Affiliation(s)
| | - Conrad P. Earnest
- Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843, USA
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30
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An Integrated, Multifactorial Approach to Periodization for Optimal Performance in Individual and Team Sports. Int J Sports Physiol Perform 2018; 13:538-561. [PMID: 29848161 DOI: 10.1123/ijspp.2018-0093] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Sports periodization has traditionally focused on the exercise aspect of athletic preparation, while neglecting the integration of other elements that can impact an athlete's readiness for peak competition performances. Integrated periodization allows the coordinated inclusion of multiple training components best suited for a given training phase into an athlete's program. The aim of this article is to review the available evidence underpinning integrated periodization, focusing on exercise training, recovery, nutrition, psychological skills, and skill acquisition as key factors by which athletic preparation can be periodized. The periodization of heat and altitude adaptation, body composition, and physical therapy is also considered. Despite recent criticism, various methods of exercise training periodization can contribute to performance enhancement in a variety of elite individual and team sports, such as soccer. In the latter, both physical and strategic periodization are useful tools for managing the heavy travel schedule, fatigue, and injuries that occur throughout a competitive season. Recovery interventions should be periodized (ie, withheld or emphasized) to influence acute and chronic training adaptation and performance. Nutrient intake and timing in relation to exercise and as part of the periodization of an athlete's training and competition calendar can also promote physiological adaptations and performance capacity. Psychological skills are a central component of athletic performance, and their periodization should cater to each athlete's individual needs and the needs of the team. Skill acquisition can also be integrated into an athlete's periodized training program to make a significant contribution to competition performance.
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31
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Hawley JA, Lundby C, Cotter JD, Burke LM. Maximizing Cellular Adaptation to Endurance Exercise in Skeletal Muscle. Cell Metab 2018; 27:962-976. [PMID: 29719234 DOI: 10.1016/j.cmet.2018.04.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The application of molecular techniques to exercise biology has provided novel insight into the complexity and breadth of intracellular signaling networks involved in response to endurance-based exercise. Here we discuss several strategies that have high uptake by athletes and, on mechanistic grounds, have the potential to promote cellular adaptation to endurance training in skeletal muscle. Such approaches are based on the underlying premise that imposing a greater metabolic load and provoking extreme perturbations in cellular homeostasis will augment acute exercise responses that, when repeated over months and years, will amplify training adaptation.
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Affiliation(s)
- John A Hawley
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia.
| | - Carsten Lundby
- Centre for Physical Activity Research, Copenhagen University Hospital, Copenhagen, Denmark
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia; Department of Sport Nutrition, Australian Institute of Sport, Belconnen, ACT, Australia
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32
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Ferreira GA, Felippe LC, Silva RLS, Bertuzzi R, De Oliveira FR, Pires FO, Lima-Silva AE. Effect of pre-exercise carbohydrate availability on fat oxidation and energy expenditure after a high-intensity exercise. ACTA ACUST UNITED AC 2018; 51:e6964. [PMID: 29590260 PMCID: PMC5886548 DOI: 10.1590/1414-431x20186964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 02/02/2018] [Indexed: 11/22/2022]
Abstract
The aim of this study was to test the hypothesis that reduced pre-exercise carbohydrate (CHO) availability potentiates fat oxidation after an exhaustive high-intensity exercise bout. Eight physically active men underwent a high-intensity exercise (∼95% V̇O2max) until exhaustion under low or high pre-exercise CHO availability. The protocol to manipulate pre-exercise CHO availability consisted of a 90-min cycling bout at ∼70% V̇O2max + 6 × 1-min at 125% V̇O2max with 1-min rest, followed by 48 h under a low- (10% CHO, low-CHO availability) or high-CHO diet (80% CHO, high-CHO availability). Time to exhaustion was shorter and energy expenditure (EE) lower during the high-intensity exercise in low- compared to high-CHO availability (8.6±0.8 and 11.4±1.6 min, and 499±209 and 677±343 kJ, respectively, P<0.05). Post-exercise EE was similar between low- and high-CHO availability (425±147 and 348±54 kJ, respectively, P>0.05), but post-exercise fat oxidation was significantly higher (P<0.05) in low- (7,830±1,864 mg) than in high-CHO availability (6,264±1,763 mg). The total EE (i.e., exercise EE plus post-exercise EE) was similar between low- and high-CHO availability (924±264 and 1,026±340 kJ, respectively, P>0.05). These results suggest that a single bout of high-intensity exercise performed under low-CHO availability increased post-exercise fat oxidation, and even with shorter exercise duration, both post-exercise EE and total EE were not impaired.
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Affiliation(s)
- G A Ferreira
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil
| | - L C Felippe
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil
| | - R L S Silva
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil
| | - R Bertuzzi
- Grupo de Estudos em Desempenho Aeróbio, Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| | - F R De Oliveira
- Núcleo de Estudos do Movimento Humano, Departamento de Educação Física, Universidade Federal de Lavras, Lavras, MG, Brasil
| | - F O Pires
- Grupo de Estudos em Psico-fisiologia do Exercício, Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, SP, Brasil
| | - A E Lima-Silva
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil.,Grupo de Pesquisa Desempenho Humano, Universidade Tecnológica Federal do Paraná, Curitiba, PR, Brasil
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33
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Leckey JJ, Hoffman NJ, Parr EB, Devlin BL, Trewin AJ, Stepto NK, Morton JP, Burke LM, Hawley JA. High dietary fat intake increases fat oxidation and reduces skeletal muscle mitochondrial respiration in trained humans. FASEB J 2018; 32:2979-2991. [DOI: 10.1096/fj.201700993r] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Jill J. Leckey
- Mary MacKillop Institute for Health ResearchAustralian Catholic University Melbourne Victoria Australia
| | - Nolan J. Hoffman
- Mary MacKillop Institute for Health ResearchAustralian Catholic University Melbourne Victoria Australia
| | - Evelyn B. Parr
- Mary MacKillop Institute for Health ResearchAustralian Catholic University Melbourne Victoria Australia
| | - Brooke L. Devlin
- Mary MacKillop Institute for Health ResearchAustralian Catholic University Melbourne Victoria Australia
| | - Adam J. Trewin
- Institute of Sport, Exercise, and Active LivingCollege of Sport and Exercise ScienceVictoria University Melbourne Victoria Australia
- University of Rochester Medical Center Rochester NY USA
| | - Nigel K. Stepto
- Institute of Sport, Exercise, and Active LivingCollege of Sport and Exercise ScienceVictoria University Melbourne Victoria Australia
| | - James P. Morton
- Research Institute for Sport and Exercise SciencesLiverpool John Moores University Liverpool United Kingdom
| | - Louise M. Burke
- Mary MacKillop Institute for Health ResearchAustralian Catholic University Melbourne Victoria Australia
- Australian Institute of Sport Canberra Australian Capital Territory Australia
| | - John A. Hawley
- Mary MacKillop Institute for Health ResearchAustralian Catholic University Melbourne Victoria Australia
- Research Institute for Sport and Exercise SciencesLiverpool John Moores University Liverpool United Kingdom
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34
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Purdom T, Kravitz L, Dokladny K, Mermier C. Understanding the factors that effect maximal fat oxidation. J Int Soc Sports Nutr 2018; 15:3. [PMID: 29344008 PMCID: PMC5766985 DOI: 10.1186/s12970-018-0207-1] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/02/2018] [Indexed: 12/02/2022] Open
Abstract
Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO2max, is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox). Due to limitations within FA transport across the cell and mitochondrial membranes, FAox is limited at higher exercise intensities. The point at which FAox reaches maximum and begins to decline is referred to as the crossover point. Exercise intensities that exceed the crossover point (~65% VO2max) utilize CHO as the predominant fuel source for energy supply. Training status, exercise intensity, exercise duration, sex differences, and nutrition have all been shown to affect cellular expression responsible for FAox rate. Each stimulus affects the process of FAox differently, resulting in specific adaptions that influence endurance exercise performance. Endurance training, specifically long duration (>2 h) facilitate adaptations that alter both the origin of FAs and FAox rate. Additionally, the influence of sex and nutrition on FAox are discussed. Finally, the role of FAox in the improvement of performance during endurance training is discussed.
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Affiliation(s)
- Troy Purdom
- 1Department of Health, Athletic Training, Recreation, and Kinesiology, Longwood University, 201 High St, Farmville, VA 23909 USA.,2Department of Health, Exercise & Sports Sciences, University of New Mexico, Albuquerque, NM USA
| | - Len Kravitz
- 2Department of Health, Exercise & Sports Sciences, University of New Mexico, Albuquerque, NM USA
| | - Karol Dokladny
- 2Department of Health, Exercise & Sports Sciences, University of New Mexico, Albuquerque, NM USA.,3Department of Gastroenterology, The University of New Mexico, Albuquerque, NM USA
| | - Christine Mermier
- 2Department of Health, Exercise & Sports Sciences, University of New Mexico, Albuquerque, NM USA
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35
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Riddell MC, Gallen IW, Smart CE, Taplin CE, Adolfsson P, Lumb AN, Kowalski A, Rabasa-Lhoret R, McCrimmon RJ, Hume C, Annan F, Fournier PA, Graham C, Bode B, Galassetti P, Jones TW, Millán IS, Heise T, Peters AL, Petz A, Laffel LM. Exercise management in type 1 diabetes: a consensus statement. Lancet Diabetes Endocrinol 2017; 5:377-390. [PMID: 28126459 DOI: 10.1016/s2213-8587(17)30014-1] [Citation(s) in RCA: 501] [Impact Index Per Article: 71.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 11/20/2016] [Accepted: 11/21/2016] [Indexed: 12/28/2022]
Abstract
Type 1 diabetes is a challenging condition to manage for various physiological and behavioural reasons. Regular exercise is important, but management of different forms of physical activity is particularly difficult for both the individual with type 1 diabetes and the health-care provider. People with type 1 diabetes tend to be at least as inactive as the general population, with a large percentage of individuals not maintaining a healthy body mass nor achieving the minimum amount of moderate to vigorous aerobic activity per week. Regular exercise can improve health and wellbeing, and can help individuals to achieve their target lipid profile, body composition, and fitness and glycaemic goals. However, several additional barriers to exercise can exist for a person with diabetes, including fear of hypoglycaemia, loss of glycaemic control, and inadequate knowledge around exercise management. This Review provides an up-to-date consensus on exercise management for individuals with type 1 diabetes who exercise regularly, including glucose targets for safe and effective exercise, and nutritional and insulin dose adjustments to protect against exercise-related glucose excursions.
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Affiliation(s)
- Michael C Riddell
- Muscle Health Research Centre, York University, Toronto, ON, Canada.
| | - Ian W Gallen
- Royal Berkshire NHS Foundation Trust Centre for Diabetes and Endocrinology, Royal Berkshire Hospital, Reading, UK
| | - Carmel E Smart
- Hunter Medical Research Institute, School of Health Sciences, University of Newcastle, Rankin Park, NSW, Australia
| | - Craig E Taplin
- Division of Endocrinology and Diabetes, Department of Pediatrics, University of Washington, Seattle Children's Hospital, Seattle, WA, USA
| | - Peter Adolfsson
- Department of Pediatrics, The Hospital of Halland, Kungsbacka, Sweden; Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Alistair N Lumb
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK
| | - Aaron Kowalski
- Juvenile Diabetes Research Foundation, New York, NY, USA
| | - Remi Rabasa-Lhoret
- Department of Nutrition and Institut de Recherches Cliniques de Montréal, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Rory J McCrimmon
- Division of Molecular and Clinical Medicine, School of Medicine, University of Dundee, Dundee, UK
| | | | - Francesca Annan
- Children and Young People's Diabetes Service, University College London Hospitals NHS Foundation Trust, London, UK
| | - Paul A Fournier
- School of Sport Science, Exercise, and Health, Perth, WA, Australia
| | | | - Bruce Bode
- Atlanta Diabetes Associates, Atlanta, GA, USA
| | - Pietro Galassetti
- Department of Pediatrics, University of California Irvine, Irvine, CA, USA; AstraZeneca, Gaithersburg, MD, USA
| | - Timothy W Jones
- The University of Western Australia, Perth, WA, Australia; Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, Perth, WA, Australia; Telethon Kids Institute, Perth, WA, Australia
| | - Iñigo San Millán
- Department of Physical Medicine and Rehabilitation, University of Colorado, School of Medicine, Aurora, CO, USA
| | | | - Anne L Peters
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Lori M Laffel
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, USA; Pediatric, Adolescent and Young Adult Section, Joslin Diabetes Center, Boston, MA, USA
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36
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Abstract
It is becoming increasingly clear that adaptations, initiated by exercise, can be amplified or reduced by nutrition. Various methods have been discussed to optimize training adaptations and some of these methods have been subject to extensive study. To date, most methods have focused on skeletal muscle, but it is important to note that training effects also include adaptations in other tissues (e.g., brain, vasculature), improvements in the absorptive capacity of the intestine, increases in tolerance to dehydration, and other effects that have received less attention in the literature. The purpose of this review is to define the concept of periodized nutrition (also referred to as nutritional training) and summarize the wide variety of methods available to athletes. The reader is referred to several other recent review articles that have discussed aspects of periodized nutrition in much more detail with primarily a focus on adaptations in the muscle. The purpose of this review is not to discuss the literature in great detail but to clearly define the concept and to give a complete overview of the methods available, with an emphasis on adaptations that are not in the muscle. Whilst there is good evidence for some methods, other proposed methods are mere theories that remain to be tested. 'Periodized nutrition' refers to the strategic combined use of exercise training and nutrition, or nutrition only, with the overall aim to obtain adaptations that support exercise performance. The term nutritional training is sometimes used to describe the same methods and these terms can be used interchangeably. In this review, an overview is given of some of the most common methods of periodized nutrition including 'training low' and 'training high', and training with low- and high-carbohydrate availability, respectively. 'Training low' in particular has received considerable attention and several variations of 'train low' have been proposed. 'Training-low' studies have generally shown beneficial effects in terms of signaling and transcription, but to date, few studies have been able to show any effects on performance. In addition to 'train low' and 'train high', methods have been developed to 'train the gut', train hypohydrated (to reduce the negative effects of dehydration), and train with various supplements that may increase the training adaptations longer term. Which of these methods should be used depends on the specific goals of the individual and there is no method (or diet) that will address all needs of an individual in all situations. Therefore, appropriate practical application lies in the optimal combination of different nutritional training methods. Some of these methods have already found their way into training practices of athletes, even though evidence for their efficacy is sometimes scarce at best. Many pragmatic questions remain unanswered and another goal of this review is to identify some of the remaining questions that may have great practical relevance and should be the focus of future research.
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Affiliation(s)
- Asker E Jeukendrup
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
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37
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Burke LM, Ross ML, Garvican-Lewis LA, Welvaert M, Heikura IA, Forbes SG, Mirtschin JG, Cato LE, Strobel N, Sharma AP, Hawley JA. Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers. J Physiol 2017; 595:2785-2807. [PMID: 28012184 PMCID: PMC5407976 DOI: 10.1113/jp273230] [Citation(s) in RCA: 250] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/23/2016] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support. Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole-body fat oxidation during exercise in race walkers over a range of exercise intensities. The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real-life race performance in elite race walkers. In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity. ABSTRACT We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world-class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg-1 day-1 : 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day-1 CHO; 78% energy as fat; 2.1 g kg-1 day-1 protein; LCHF, n = 10). Post-intervention, V̇O2 peak during race walking increased in all groups (P < 0.001, 90% CI: 2.55, 5.20%). LCHF was associated with markedly increased rates of whole-body fat oxidation, attaining peak rates of 1.57 ± 0.32 g min-1 during 2 h of walking at ∼80% V̇O2 peak . However, LCHF also increased the oxygen (O2 ) cost of race walking at velocities relevant to real-life race performance: O2 uptake (expressed as a percentage of new V̇O2 peak ) at a speed approximating 20 km race pace was reduced in HCHO and PCHO (90% CI: -7.047, -2.55 and -5.18, -0.86, respectively), but was maintained at pre-intervention levels in LCHF. HCHO and PCHO groups improved times for 10 km race walk: 6.6% (90% CI: 4.1, 9.1%) and 5.3% (3.4, 7.2%), with no improvement (-1.6% (-8.5, 5.3%)) for the LCHF group. In contrast to training with diets providing chronic or periodised high-CHO availability, and despite a significant improvement in V̇O2 peak , adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy.
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Affiliation(s)
- Louise M Burke
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia, 3000
| | - Megan L Ross
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia, 3000
| | - Laura A Garvican-Lewis
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia, 3000
| | - Marijke Welvaert
- University of Canberra Research Institute for Sport and Exercise, Canberra, Australia, 2617.,Innovation, Research and Development, Australian Institute of Sport, Canberra, Australia, 2616
| | - Ida A Heikura
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia, 3000
| | - Sara G Forbes
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616
| | - Joanne G Mirtschin
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616
| | - Louise E Cato
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia, 2616
| | | | - Avish P Sharma
- Physiology, Australian Institute of Sport, Canberra, Australia, 2616
| | - John A Hawley
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia, 3000.,Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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38
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TAKAHASHI Y, MATSUNAGA Y, TAMURA Y, TERADA S, HATTA H. Pre-Exercise High-Fat Diet for 3 Days Affects Post-Exercise Skeletal Muscle Glycogen Repletion. J Nutr Sci Vitaminol (Tokyo) 2017; 63:323-330. [DOI: 10.3177/jnsv.63.323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | - Yuki TAMURA
- Department of Sports Sciences, The University of Tokyo
| | - Shin TERADA
- Department of Sports Sciences, The University of Tokyo
| | - Hideo HATTA
- Department of Sports Sciences, The University of Tokyo
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39
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Pöchmüller M, Schwingshackl L, Colombani PC, Hoffmann G. A systematic review and meta-analysis of carbohydrate benefits associated with randomized controlled competition-based performance trials. J Int Soc Sports Nutr 2016; 13:27. [PMID: 27408608 PMCID: PMC4940907 DOI: 10.1186/s12970-016-0139-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/28/2016] [Indexed: 11/10/2022] Open
Abstract
Background Carbohydrate supplements are widely used by athletes as an ergogenic aid before and during sports events. The present systematic review and meta-analysis aimed at synthesizing all available data from randomized controlled trials performed under real-life conditions. Methods MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched systematically up to February 2015. Study groups were categorized according to test mode and type of performance measurement. Subgroup analyses were done with reference to exercise duration and range of carbohydrate concentration. Random effects and fixed effect meta-analyses were performed using the Software package by the Cochrane Collaboration Review Manager 5.3. Results Twenty-four randomized controlled trials met the objectives and were included in the present systematic review, 16 of which provided data for meta-analyses. Carbohydrate supplementations were associated with a significantly shorter exercise time in groups performing submaximal exercise followed by a time trial [mean difference −0.9 min (95 % confidence interval −1.7, −0.2), p = 0.02] as compared to controls. Subgroup analysis showed that improvements were specific for studies administering a concentration of carbohydrates between 6 and 8 % [mean difference −1.0 min (95 % confidence interval −1.9, −0.0), p = 0.04]. Concerning groups with submaximal exercise followed by a time trial measuring power accomplished within a fixed time or distance, mean power output was significantly higher following carbohydrate load (mean difference 20.2 W (95 % confidence interval 9.0, 31.5), p = 0.0004]. Likewise, mean power output was significantly increased following carbohydrate intervention in groups with time trial measuring power within a fixed time or distance (mean difference 8.1 W (95 % confidence interval 0.5, 15.7) p = 0.04]. Conclusion Due to the limitations of this systematic review, results can only be applied to a subset of athletes (trained male cyclists). For those, we could observe a potential ergogenic benefit of carbohydrate supplementation especially in a concentration range between 6 and 8 % when exercising longer than 90 min. Electronic supplementary material The online version of this article (doi:10.1186/s12970-016-0139-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin Pöchmüller
- Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Althanstraße 14 (UZAII), A-1090 Vienna, Austria
| | - Lukas Schwingshackl
- German Institute of Human Nutrition, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Paolo C Colombani
- Swiss Federal Institute of Sport Magglingen (SFISM), CH-2532 Magglingen, Switzerland
| | - Georg Hoffmann
- Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Althanstraße 14 (UZAII), A-1090 Vienna, Austria
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Volek JS, Freidenreich DJ, Saenz C, Kunces LJ, Creighton BC, Bartley JM, Davitt PM, Munoz CX, Anderson JM, Maresh CM, Lee EC, Schuenke MD, Aerni G, Kraemer WJ, Phinney SD. Metabolic characteristics of keto-adapted ultra-endurance runners. Metabolism 2016; 65:100-10. [PMID: 26892521 DOI: 10.1016/j.metabol.2015.10.028] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/26/2015] [Accepted: 10/27/2015] [Indexed: 01/31/2023]
Abstract
BACKGROUND Many successful ultra-endurance athletes have switched from a high-carbohydrate to a low-carbohydrate diet, but they have not previously been studied to determine the extent of metabolic adaptations. METHODS Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO2max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n=10, %carbohydrate:protein:fat=59:14:25) diet, and the other a low-carbohydrate (LC; n=10, 10:19:70) diet for an average of 20 months (range 9 to 36 months). RESULTS Peak fat oxidation was 2.3-fold higher in the LC group (1.54±0.18 vs 0.67±0.14 g/min; P=0.000) and it occurred at a higher percentage of VO2max (70.3±6.3 vs 54.9±7.8%; P=0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21±0.02 vs 0.76±0.11 g/min; P=0.000) corresponding to a greater relative contribution of fat (88±2 vs 56±8%; P=0.000). Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (-64% from pre-exercise) and 120 min of recovery (-36% from pre-exercise). CONCLUSION Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.
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Affiliation(s)
- Jeff S Volek
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA; Department of Human Sciences, The Ohio State University, Columbus, OH, USA.
| | - Daniel J Freidenreich
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA; Department of Human Sciences, The Ohio State University, Columbus, OH, USA
| | - Catherine Saenz
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA; Department of Human Sciences, The Ohio State University, Columbus, OH, USA
| | - Laura J Kunces
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Brent C Creighton
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Jenna M Bartley
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Patrick M Davitt
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Colleen X Munoz
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | | | - Carl M Maresh
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA; Department of Human Sciences, The Ohio State University, Columbus, OH, USA
| | - Elaine C Lee
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Mark D Schuenke
- Department of Anatomy, University of New England, Biddeford, ME, USA
| | - Giselle Aerni
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - William J Kraemer
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA; Department of Human Sciences, The Ohio State University, Columbus, OH, USA
| | - Stephen D Phinney
- School of Medicine (emeritus), University of California, Davis, Davis, CA, USA
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Devries MC. Sex-based differences in endurance exercise muscle metabolism: impact on exercise and nutritional strategies to optimize health and performance in women. Exp Physiol 2015; 101:243-9. [PMID: 26459076 DOI: 10.1113/ep085369] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 10/08/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? The topic is how sex influences carbohydrate and fat metabolism during exercise and whether this influences adaptation to nutritional and exercise regimens aiming to improve health and performance. What advances does it highlight? Women respond differently to certain nutritional and training regimens aimed at improving health and performance. Few studies have included women in trials and thus we are unsure how women respond to nutritional and training strategies aimed at improving health and performance. Sex-based differences in substrate metabolism during moderate-intensity endurance exercise (END) have been well established. Specifically, during END of the same relative intensity women have a lower respiratory exchange ratio than men, indicative of a lesser reliance on carbohydrate oxidation to support fuel requirements for exercise. In fact, compared with men, women show a lesser reliance on both liver and muscle glycogen during END. Sex-based differences in intramyocellular lipid (IMCL) utilization during END are controversial. However, women have a larger depot of IMCL available to support END fuel needs and a greater percentage of IMCL in contact with mitochondria after a bout of END compared with men, suggestive of a greater capacity to use IMCL. These sex-based differences in metabolism during END are known to be mediated by oestrogen. Despite the well-recognized sexual dimorphisms in substrate metabolism during END, there is a paucity of research examining the effects of exercise and nutritional regimens aimed to enhance performance and/or health in women. Furthermore, the evidence that does exist is suggestive of discordance in the effectiveness of nutritional and exercise regimens between the sexes. The focus of this review is to provide an overview of the well-established sex-based differences in metabolism during END and how they relate to the physiological responses to nutritional and exercise strategies intended to improve exercise performance and/or health.
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Affiliation(s)
- Michaela C Devries
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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42
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Abstract
A major goal of training to improve the performance of prolonged, continuous, endurance events lasting up to 3 h is to promote a range of physiological and metabolic adaptations that permit an athlete to work at both higher absolute and relative power outputs/speeds and delay the onset of fatigue (i.e., a decline in exercise intensity). To meet these goals, competitive endurance athletes undertake a prodigious volume of training, with a large proportion performed at intensities that are close to or faster than race pace and highly dependent on carbohydrate (CHO)-based fuels to sustain rates of muscle energy production [i.e., match rates of adenosine triphosphate (ATP) hydrolysis with rates of resynthesis]. Consequently, to sustain muscle energy reserves and meet the daily demands of training sessions, competitive athletes freely select CHO-rich diets. Despite renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.
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Affiliation(s)
- John A Hawley
- The Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Locked Bag 4115, Fitzroy, VIC, 3065, Australia.
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
| | - Jill J Leckey
- The Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Locked Bag 4115, Fitzroy, VIC, 3065, Australia
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Abstract
During the period 1985-2005, studies examined the proposal that adaptation to a low-carbohydrate (<25 % energy), high-fat (>60 % energy) diet (LCHF) to increase muscle fat utilization during exercise could enhance performance in trained individuals by reducing reliance on muscle glycogen. As little as 5 days of training with LCHF retools the muscle to enhance fat-burning capacity with robust changes that persist despite acute strategies to restore carbohydrate availability (e.g., glycogen supercompensation, carbohydrate intake during exercise). Furthermore, a 2- to 3-week exposure to minimal carbohydrate (<20 g/day) intake achieves adaptation to high blood ketone concentrations. However, the failure to detect clear performance benefits during endurance/ultra-endurance protocols, combined with evidence of impaired performance of high-intensity exercise via a down-regulation of carbohydrate metabolism led this author to dismiss the use of such fat-adaptation strategies by competitive athletes in conventional sports. Recent re-emergence of interest in LCHF diets, coupled with anecdotes of improved performance by sportspeople who follow them, has created a need to re-examine the potential benefits of this eating style. Unfortunately, the absence of new data prevents a different conclusion from being made. Notwithstanding the outcomes of future research, there is a need for better recognition of current sports nutrition guidelines that promote an individualized and periodized approach to fuel availability during training, allowing the athlete to prepare for competition performance with metabolic flexibility and optimal utilization of all muscle substrates. Nevertheless, there may be a few scenarios where LCHF diets are of benefit, or at least are not detrimental, for sports performance.
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Affiliation(s)
- Louise M Burke
- Sports Nutrition, Australian Institute of Sport, Canberra, ACT, Australia.
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia.
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Noland RC. Exercise and Regulation of Lipid Metabolism. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 135:39-74. [PMID: 26477910 DOI: 10.1016/bs.pmbts.2015.06.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The increased prevalence of hyperlipidemia, hypertriglyceridemia, hypercholesterolemia, and fatty liver disease has provided increasingly negative connotations toward lipids. However, it is important to remember that lipids are essential components supporting life. Lipids are a class of molecules defined by their inherent insolubility in water. In biological systems, lipids are either hydrophobic (containing only polar groups) or amphipathic (possess polar and nonpolar groups). These characteristics lend lipids to be highly diverse with a multitude of functions including hormone and membrane synthesis, involvement in numerous signaling cascades, as well as serving as a source of metabolic fuel supporting energy production. Exercise can induce changes in the lipid composition of membranes that effect fluidity and cellular function, as well as modify the cellular and circulating environment of lipids that regulate signaling cascades. The purpose of this chapter is to focus on lipid utilization as metabolic fuel in response to acute and chronic exercise training. Lipids utilized as an energy source during exercise include circulating fatty acids bound to albumin, triglycerides stored in very-low-density lipoprotein, and intramuscular triglyceride stores. Dynamic changes in these lipid pools during and after exercise are discussed, as well as key factors that may be responsible for regulating changes in fat oxidation in response to varying exercise conditions.
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Affiliation(s)
- Robert C Noland
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, USA.
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Abstract
A key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability coupled with an inability to effectively utilize alternative lipid fuel sources. Paradoxically, cognitive and physical decline associated with glycogen depletion occurs in the presence of an over-abundance of fuel stored as body fat that the athlete is apparently unable to access effectively. Current fuelling tactics that emphasize high-carbohydrate intakes before and during exercise inhibit fat utilization. The most efficient approach to accelerate the body's ability to oxidize fat is to lower dietary carbohydrate intake to a level that results in nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) while increasing fat intake for a period of several weeks. The coordinated set of metabolic adaptations that ensures proper interorgan fuel supply in the face of low-carbohydrate availability is referred to as keto-adaptation. Beyond simply providing a stable source of fuel for the brain, the major circulating ketone body, beta-hydroxybutyrate, has recently been shown to act as a signalling molecule capable of altering gene expression, eliciting complementary effects of keto-adaptation that could extend human physical and mental performance beyond current expectation. In this paper, we review these new findings and propose that the shift to fatty acids and ketones as primary fuels when dietary carbohydrate is restricted could be of benefit for some athletes.
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Affiliation(s)
- Jeff S Volek
- a Kinesiology Program, Department of Human Sciences , The Ohio State University , Columbus , OH , USA
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Frost EA, Redman LM, de Jonge L, Rood J, Zachwieja JJ, Volaufova J, Bray GA, Smith SR. Interaction between dietary fat and exercise on excess postexercise oxygen consumption. Am J Physiol Endocrinol Metab 2014; 306:E1093-8. [PMID: 24644241 PMCID: PMC4010654 DOI: 10.1152/ajpendo.00383.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to determine the effect of increased physical activity on subsequent sleeping energy expenditure (SEE) measured in a whole room calorimeter under differing levels of dietary fat. We hypothesized that increased physical activity would increase SEE. Six healthy young men participated in a randomized, single-blind, crossover study. Subjects repeated an 8-day protocol under four conditions separated by at least 7 days. During each condition, subjects consumed an isoenergetic diet consisting of 37% fat, 15% protein, and 48% carbohydrate for the first 4 days, and for the following 4 days SEE and energy balance were measured in a respiration chamber. The first chamber day served as a baseline measurement, and for the remaining 3 days diet and activity were randomly assigned as high-fat/exercise, high-fat/sedentary, low-fat/exercise, or low-fat/sedentary. Energy balance was not different between conditions. When the dietary fat was increased to 50%, SEE increased by 7.4% during exercise (P < 0.05) relative to being sedentary (baseline day), but SEE did not increase with exercise when fat was lowered to 20%. SEE did not change when dietary fat was manipulated under sedentary conditions. Physical activity causes an increase in SEE when dietary fat is high (50%) but not when dietary fat is low (20%). Dietary fat content influences the impact of postexercise-induced increases in SEE. This finding may help explain the conflicting data regarding the effect of exercise on energy expenditure.
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Trewin AJ, Petersen AC, Billaut F, McQuade LR, McInerney BV, Stepto NK. N-acetylcysteine alters substrate metabolism during high-intensity cycle exercise in well-trained humans. Appl Physiol Nutr Metab 2013; 38:1217-27. [PMID: 24195622 DOI: 10.1139/apnm-2012-0482] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We investigated the effects of N-acetylcysteine (NAC) on metabolism during fixed work rate high-intensity interval exercise (HIIE) and self-paced 10-min time-trial (TT10) performance. Nine well-trained male cyclists (V̇O2peak, 69.4 ± 5.8 mL · kg(-1) · min(-1); peak power output (PPO), 385 ± 43 W; mean ± SD) participated in a double-blind, repeated-measures, randomised crossover trial. Two trials (NAC supplementation and placebo) were performed 7 days apart consisting of 6 × 5 min HIIE bouts at 82% PPO (316 ± 40 W) separated by 1 min at 100 W, and then after 2 min of recovery at 100 W, TT10 was performed. Expired gases, venous blood, and electromyographic (EMG) data were collected. NAC did not influence blood glutathione but decreased lipid peroxidation compared with the placebo (P < 0.05). Fat oxidation was elevated with NAC compared with the placebo during HIIE bouts 5 and 6 (9.9 ± 8.9 vs. 3.9 ± 4.8 μmol · kg(-1) · min(-1); P < 0.05), as was blood glucose throughout HIIE (4.3 ± 0.6 vs. 3.8 ± 0.6 mmol · L(-1); P < 0.05). Blood lactate was lower with NAC after TT10 (3.3 ± 1.3 vs. 4.2 ± 1.3 mmol · L(-1); P < 0.05). Median EMG frequency of the vastus lateralis was lower with NAC during HIIE (79 ± 10 vs. 85 ± 10 Hz; P < 0.05), but not TT10 (82 ± 11 Hz). Finally, NAC decreased mean power output 4.9% ± 6.6% (effect size = -0.3 ± 0.4, mean ± 90% CI) during TT10 (305 ± 57 W vs. 319 ± 45 W). These data suggest that NAC alters substrate metabolism and muscle fibre type recruitment during HIIE, which is detrimental to time-trial performance.
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Affiliation(s)
- Adam J Trewin
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria 8001, Australia
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Décombaz J, Grathwohl D, Pollien P, Schmitt JAJ, Borrani F, Lecoultre V. Effect of short-duration lipid supplementation on fat oxidation during exercise and cycling performance. Appl Physiol Nutr Metab 2013; 38:766-72. [PMID: 23980735 DOI: 10.1139/apnm-2012-0459] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of intramyocellular lipids (IMCLs) on endurance performance with high skeletal muscle glycogen availability remains unclear. Previous work has shown that a lipid-supplemented high-carbohydrate (CHO) diet increases IMCLs while permitting normal glycogen loading. The aim of this study was to assess the effect of fat supplementation on fat oxidation (Fox) and endurance performance. Twenty-two trained male cyclists performed 2 simulated time trials (TT) in a randomized crossover design. Subjects cycled at ∼53% maximal voluntary external power for 2 h and then followed 1 of 2 diets for 2.5 days: a high-CHO low-fat (HC) diet, consisting of CHO 7.4 g·kg(-1)·day(-1) and fat 0.5 g·kg(-1)·day(-1); or a high-CHO fat-supplemented (HCF) diet, which was a replication of the HC diet with ∼240 g surplus fat (30% saturation) distributed over the last 4 meals of the diet period. On trial morning, fasting blood was sampled and Fox was measured during an incremental exercise; a ∼1-h TT followed. Breath volatile compounds (VOCs) were measured at 3 time points. Mental fatigue, measured as reaction time, was evaluated during the TT. Plasma free fatty acid concentration was 50% lower after the HCF diet (p < 0.0001), and breath acetone was reduced (p < 0.05) "at rest". Fox peaked (∼0.35 g·kg(-1)) at ∼42% peak oxygen consumption, and was not influenced by diet. Performance was not significantly different between the HCF and HC diets (3369 ± 46 s vs 3398 ± 48 s; p = 0.39), nor were reaction times to the attention task and VOCs (p = NS for both). In conclusion, the short-term intake of a lipid supplement in combination with a glycogen-loading diet designed to boost intramyocellular lipids while avoiding fat adaptation did not alter substrate oxidation during exercise or 1-hour cycling performance.
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Affiliation(s)
- Jacques Décombaz
- Nestlé Research Center, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
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Wall BT, Stephens FB, van Loon LJ, Constantin-Teodosiu D, Macdonald IA, Greenhaff PL. Reduced fat oxidation during high intensity, submaximal exercise: is the availability of carnitine important? Eur J Sport Sci 2013. [DOI: 10.1080/17461391.2011.630103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Colombani PC, Mannhart C, Mettler S. Carbohydrates and exercise performance in non-fasted athletes: a systematic review of studies mimicking real-life. Nutr J 2013; 12:16. [PMID: 23356905 PMCID: PMC3570376 DOI: 10.1186/1475-2891-12-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 01/22/2013] [Indexed: 11/10/2022] Open
Abstract
There is a consensus claiming an ergogenic effect of carbohydrates ingested in the proximity of or during a performance bout. However, in performance studies, the protocols that are used are often highly standardized (e.g. fasted subjects, constant exercise intensity with time-to-exhaustion tests), and do not necessarily reflect competitive real-life situations. Therefore, we aimed at systematically summarizing all studies with a setting mimicking the situation of a real-life competition (e.g., subjects exercising in the postprandial state and with time-trial-like performance tests such as fixed distance or fixed time tests). We performed a PubMed search by using a selection of search terms covering inclusion criteria for sport, athletes, carbohydrates, and fluids, and exclusion criteria for diseases and animals. This search yielded 16,658 articles and the abstract of 16,508 articles contained sufficient information to identify the study as non-eligible for this review. The screening of the full text of the remaining 150 articles yielded 17 articles that were included in this review. These articles described 22 carbohydrate interventions covering test durations from 26 to 241 min (mostly cycling). We observed no performance improvement with half of the carbohydrate interventions, while the other half of the interventions had significant improvement between 1% and 13% (improvement with one of five interventions lasting up to 68 min and with 10 of 17 interventions lasting between 70 and 241 min). Thus, when considering only studies with a setting mimicking real-life competition, there is a mixed general picture about the ergogenic effect of carbohydrates ingested in the proximity of or during a performance bout with an unlikely effect with bouts up to perhaps 70 min and a possible but not compelling ergogenic effect with performance durations longer than about 70 min.
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