Preprint / Version 1

Ketogenic and High-Carbohydrate Diets in Cyclists and Triathletes

Performance Indicators and Methodological Considerations From a Pilot Study

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DOI:

https://doi.org/10.51224/SRXIV.19

Keywords:

Endurance Performance, Fat Adaptation, Muscle Glycogen, Ultrasound, Sports Nutrition, Substrate Oxidation

Abstract

Endurance athletes frequently employ nutritional strategies to enhance performance. While professional organizations recommend high carbohydrate (HC) diets to maximize performance, many athletes, and researchers have recently shown renewed interest in the ketogenic diet (KD) in hopes to promote “fat adaptation”, which would allow athletes to make use of the essentially unlimited energy resources from stored body fat. This would circumvent one fatigue mechanism, the depletion of muscle glycogen stores, that has been considered central to performance outcomes in endurance events. The present study investigated the effects of participants’ habitual diet (HD), HC, and KD on endurance performance in a 30-km simulated cycling time trial (TT), physiological responses during the TT, and muscle session fuel percentile (SFP) before and after the TT using ultrasonic imaging. Due to the COVID-19 pandemic, data collection ceased after only six recreational cyclists and triathletes (f = 4, m = 6; age: 37.2 ± 12.2; V̇O2max: 46.8 ± 6.8 ml/kg/min; weekly cycling distance: 225.3 ± 64.2 km). Due to the small sample size, we do not report inferential statistics for our primary outcome measure, cycling performance. Participants completed the KD at the lowest power output. Oxygen consumption (V̇O2), heart rate (HR), and perceived exertion (RPE) during the TT were similar in all conditions. FATox rates were highest in the KD condition and lowest in the HC condition. SFP was lower during KD compared with HD and lower following the TT compared with fasted resting values across all conditions. We discuss methodological considerations into the use of exercise equipment, nutritional interventions, and statistical analysis strategies for study designs like the present. Further research is needed to assess the impact of HC and KD on TT performance in this population.

ClinicalTrials.gov Identifier: NCT04097171; OSF preregistration: https://osf.io/ujx6e/

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References

Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Med Sci Sports Exerc 48: 543–568, 2016. doi: 10.1249/MSS.0000000000000852.

Jeukendrup AE. Carbohydrate Intake During Exercise and Performance. Nutrition 20: 669–77, 2004. doi: 10.1016/j.nut.2004.04.017.

Jeukendrup AE. Nutrition for Endurance Sports: Marathon, Triathlon, and Road Sycling. J Sports Sci 29 Suppl 1: S91-99, 2011. doi: 10.1080/02640414.2011.610348.

Burke L. Low Carb High Fat (LCHF) Diets for Athletes – Third Time Lucky? J Sci Med Sport 20: S1, 2017. doi: 10/ghp7b8.

Feinman RD, Pogozelski WK, Astrup A, Bernstein RK, Fine EJ, Westman EC, Accurso A, Frassetto L, Gower BA, McFarlane SI, Nielsen JV, Krarup T, Saslow L, Roth KS, Vernon MC, Volek JS, Wilshire GB, Dahlqvist A, Sundberg R, Childers A, Morrison K, Manninen AH, Dashti HM, Wood RJ, Wortman J, Worm N. Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base. Nutrition 31: 1–13, 2015. doi: 10.1016/j.nut.2014.06.011.

Carey AL, Staudacher HM, Cummings NK, Stepto NK, Nikolopoulos V, Burke LM, Hawley JA. Effects of Fat Adaptation and Carbohydrate Restoration on Prolonged Endurance Exercise. J Appl Physiol (1985) 91: 115–122, 2001. doi: 10.1152/jappl.2001.91.1.115.

Lambert EV, Speechly DP, Dennis SC, Noakes TD. Enhanced Endurance in Trained Cyclists During Moderate Intensity Exercise Following 2 Weeks Adaptation to a High Fat Diet. Eur J Appl Physiol Occup Physiol 69: 287–293, 1994. doi: 10.1007/bf00392032.

Lambert EV, Hawley JA, Goedecke J, Noakes TD, Dennis SC. Nutritional Strategies for Promoting Fat Utilization and Delaying the Onset of Fatigue During Prolonged Exercise. J Sports Sci 15: 315–24, 1997. doi: 10.1080/026404197367326.

Kenney WL, Wilmore JH, Costill DL. Physiology of Sport and Exercise. 7th ed. Champaing, IL: Human Kinetics, 2020.

Burke LM, Castell LM, Casa DJ, Close GL, Costa RJS, Desbrow B, Halson SL, Lis DM, Melin AK, Peeling P, Saunders PU, Slater GJ, Sygo J, Witard OC, Bermon S, Stellingwerff T. International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics. Int J Sport Nutr Exerc Metab 29: 73–84, 2019. doi: 10/gjbrp2.

Kerksick CM, Arent S, Schoenfeld BJ, Stout JR, Campbell B, Wilborn CD, Taylor L, Kalman D, Smith-Ryan AE, Kreider RB, Willoughby D, Arciero PJ, VanDusseldorp TA, Ormsbee MJ, Wildman R, Greenwood M, Ziegenfuss TN, Aragon AA, Antonio J. International Society of Sports Nutrition Position Stand: Nutrient Timing. J Int Soc Sports Nutr 14: 33, 2017. doi: 10/gg2nh6.

Galbo H, Holst JJ, Christensen NJ. The Effect of Different Diets and of Insulin on the Hormonal Response to Prolonged Exercise. Acta Physiol Scand 107: 19–32, 1979. doi: 10.1111/j.1748-1716.1979.tb06438.x.

Pitsiladis YP, Maughan RJ. The Effects of Exercise and Diet Manipulation on the Capacity to Perform Prolonged Exercise in the Heat and in the Cold in Trained Humans. J Physiol 517: 919–930, 1999. doi: 10.1111/j.1469-7793.1999.0919s.x.

Goedecke JH, Christie C, Wilson G, Dennis SC, Noakes TD, Hopkins WG, Lambert EV. Metabolic Adaptations to a High-Fat Diet in Endurance Cyclists. Metab Clin Exp 48: 1509–1517, 1999. doi: 10.1016/s0026-0495(99)90238-x.

Burke LM, Hawley JA. Effects of Short-Term Fat Adaptation on Metabolism and Performance of Prolonged Exercise. Med Sci Sports Exerc 34: 1492–1498, 2002. doi: 10.1097/00005768-200209000-00015.

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 599: 771–790, 2021. doi: 10/ghvh2b.

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 65: 100–110, 2016. doi: 10.1016/j.metabol.2015.10.028.

Burke LM, Angus DJ, Cox GR, Cummings NK, Febbraio MA, Gawthorn K, Hawley JA, Minehan M, Martin DT, Hargreaves M. Effect of Fat Adaptation and Carbohydrate Restoration on Metabolism and Performance During Prolonged Cycling. J Appl Physiol (1985) 89: 2413–2421, 2000. doi: 10.1152/jappl.2000.89.6.2413.

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 595: 2785–2807, 2017. doi: 10.1113/JP273230.

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 15: e0234027, 2020. doi: 10/gg23h5.

Durkalec-Michalski K, Nowaczyk PM, Siedzik K. Effect of a Four-Week Ketogenic Diet on Exercise Metabolism in Crossfit-Trained Athletes. J Int Soc Sports Nutr 16: 16, 2019. doi: 10.1186/s12970-019-0284-9.

McSwiney FT, Wardrop B, Hyde PN, Lafountain RA, Volek JS, Doyle L. Keto-Adaptation Enhances Exercise Performance and Body Composition Responses to Training in Endurance Athletes. Metabolism 81: 25–34, 2018. doi: 10.1016/j.metabol.2017.10.010.

Prins PJ, Noakes TD, Welton GL, Haley SJ, Esbenshade NJ, Atwell AD, Scott KE, Abraham J, Raabe AS, Buxton JD, Ault DL. High Rates of Fat Oxidation Induced by a Low-Carbohydrate, High-Fat Diet, Do Not Impair 5-km Running Performance in Competitive Recreational Athletes. J Sports Sci Med 18: 738–750, 2019.

Stepto NK, Carey AL, Staudacher HM, Cummings NK, Burke LM, Hawley JA. Effect of Short-Term Fat Adaptation on High-Intensity Training. Med Sci Sports Exerc 34: 449–455, 2002. doi: 10.1097/00005768-200203000-00011.

Zinn C, Wood M, Williden M, Chatterton S, Maunder E. Ketogenic Diet Benefits Body Composition and Well-Being but Not Performance in a Pilot Case Study of New Zealand Endurance Athletes. J Int Soc Sports Nutr 14, 2017. doi: 10.1186/s12970-017-0180-0.

Shaw DM, Merien F, Braakhuis A, Maunder ED, Dulson DK. Effect of a Ketogenic Diet on Submaximal Exercise Capacity and Efficiency in Runners. Med Sci Sports Exerc 51: 2135–2146, 2019. doi: 10.1249/MSS.0000000000002008.

Bergström J, Hultman E. A Study of the Glycogen Metabolism During Exercise in Man. Scand J Clin Lab 19: 218–228, 1967. doi: 10.3109/00365516709090629.

Phinney SD, Bistrian BR, Evans WJ, Gervino E, Blackburn GL. The Human Metabolic Response to Chronic Ketosis Without Caloric Restriction: Preservation of Submaximal Exercise Capability With Reduced Carbohydrate Oxidation. Metab Clin Exp 32: 769–776, 1983. doi: 10.1016/0026-0495(83)90106-3.

Hill JC, San Millán I. Validation of Musculoskeletal Ultrasound to Assess and Quantify Muscle Glycogen Content. A Novel Approach. Physician Sportsmed 42: 45–52, 2014. doi: 10.3810/psm.2014.09.2075.

Snow G. blockrand: Randomization for block random clinical trials [Online]. https://CRAN.R-project.org/package=blockrand [26 Oct. 2019].

R Core Team. R: A language and environment for Statistical computing [Online]. https://www.R-project.org/.

Shan Z, Rehm CD, Rogers G, Ruan M, Wang DD, Hu FB, Mozaffarian D, Zhang FF, Bhupathiraju SN. Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016. JAMA 322: 1178–1187, 2019. doi: 10/ggdhbs.

American College of Sports Medicine. Acsm’s Guidelines for Exercise Testing and Prescription. 10th ed. Philadelphia, PA: Wolters Kluwer Health, 2018.

Basset FA, Boulay MR. Specificity of Treadmill and Cycle Ergometer Tests in Triathletes, Runners and Cyclists. Eur J Appl Physiol 81: 214–221, 2000. doi: 10.1007/s004210050033.

De Pauw K, Roelands B, Cheung SS, de Geus B, Rietjens G, Meeusen R. Guidelines to Classify Subject Groups in Sport-Science Research. Int J Sports Physiol Perform 8: 111–122, 2013. doi: 10/f4nt76.

Decroix L, De Pauw K, Foster C, Meeusen R. Guidelines to Classify Female Subject Groups in Sport-Science Research. Int J Sports Physiol Perform 11: 204–213, 2016. doi: 10/ggcfjx.

Graybeal AJ, Kreutzer A, Rack P, Moss K, Augsburger G, Willis JL, Braun-Trocchio R, Shah M. Perceptions of Appetite Do Not Match Hormonal Measures of Appetite in Trained Competitive Cyclists and Triathletes Following a Ketogenic Diet Compared to a High-Carbohydrate or Habitual Diet: A Randomized Crossover Trial. Nutr Res 93: 111–123, 2021. doi: 10/gmmtch.

Lakens D, Caldwell AR. Simulation-Based Power Analysis for Factorial Analysis of Variance Designs. AMPPS 4: 2515245920951503, 2021. doi: 10/gj2hw8.

Whelton PK, Carey RM, Aronow WS, Casey DE, Collins KJ, Himmelfarb CD, DePalma SM, Gidding S, Jamerson KA, Jones DW, MacLaughlin EJ, Muntner P, Ovbiagele B, Smith SC, Spencer CC, Stafford RS, Taler SJ, Thomas RJ, Williams KA, Williamson JD, Wright JT. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 71: e127–e248, 2018. doi: 10.1016/j.jacc.2017.11.006.

Misra S, Oliver NS. Utility of Ketone Measurement in the Prevention, Diagnosis and Management of Diabetic Ketoacidosis. Diabet Med 32: 14–23, 2015. doi: 10.1111/dme.12604.

Sparks AS, Williams EL, Jones HJ, Bridge CA, Marchant D, McNaughton L. Test-retest reliability of a 16.1 km time trial in trained cyclists using the CompuTrainer ergometer. J Sci Cycl 5: 35–41, 2016. doi: 10.28985/jsc.v5i3.272.

Péronnet F, Massicotte D. Table of Nonprotein Respiratory Quotient: An Update. J Canad Sci Sport 16: 23–29, 1991.

Nieman DC, Shanely RA, Zwetsloot KA, Meaney MP, Farris GE. Ultrasonic Assessment of Exercise-Induced Change in Skeletal Muscle Glycogen Content. BMC Sports Sci Med Rehabil 7: 9, 2015. doi: 10/gb3pw8.

Bone JL, Ross ML, Tomcik KA, Jeacocke NA, McKay AKA, Burke LM. The Validity of Ultrasound Technology in Providing an Indirect Estimate of Muscle Glycogen Concentrations Is Equivocal. Nutrients 13: 2371, 2021. doi: 10/gmmtcg.

Routledge HE, Bradley WJ, Shepherd SO, Cocks M, Erskine RM, Close GL, Morton JP. Ultrasound Does Not Detect Acute Changes in Glycogen in Vastus Lateralis of Man. Med Sci Sports Exerc 51: 2286–2293, 2019. doi: 10/gmmtcf.

The MuscleHealth Company. Position Stand. Science and Application. Denver, CO: 2018.

van Buuren S, Groothuis-Oudshoorn K. MICE: Multivariate Imputation by Chained Equations in R. J Stat Softw 45: 1–67, 2011. doi: https://doi.org/10.18637/jss.v045.i03.

Schafer JL, Yucel RM. Computational Strategies for Multivariate Linear Mixed-Effects Models With Missing Values. J Comput Graph Stat 11: 437–457, 2012. doi: 10/b4r25x.

Bates D, Maechler M, Bolker B, Walker S, Singmann H, Dai B, Scheipl F, Grothendieck G, Green P, Fox J, Green P, Fox J. lme4: Linear Mixed-Effects Models using “Eigen” and S4 [Online]. https://CRAN.R-project.org/package=lme4 [25 Oct. 2019].

Lenth R. emmeans: Estimated Marginal Means, aka Least-Squares Means. R package version 1.4.1. [Online]. https://CRAN.R-project.org/package=emmeans.

Hopkins WG, Schabort EJ, Hawley JA. Reliability of Power in Physical Performance Tests. Sports Med 31: 211–234, 2001. doi: 10/c2mfh9.

Gribble S. An interactive model-based calculator of cycling power vs. speed [Online]. The Computational Cyclist: [date unknown]. https://www.gribble.org/cycling/power_v_speed.html [5 Sep. 2021].

Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women. J Clin Endocrinol Metab 88: 1617–1623, 2003. doi: 10.1210/jc.2002-021480.

Brehm BJ, Spang SE, Lattin BL, Seeley RJ, Daniels SR, D’Alessio DA. The Role of Energy Expenditure in the Differential Weight Loss in Obese Women on Low-Fat and Low-Carbohydrate Diets. The Journal of Clinical Endocrinology & Metabolism 90: 1475–1482, 2005. doi: 10.1210/jc.2004-1540.

Yancy WS, Olsen MK, Guyton JR, Bakst RP, Westman EC. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treat Obesity and Hyperlipidemia. Ann Intern Med 140: 769–777, 2004. doi: 10/gf9nd9.

Worme JD, Doubt TJ, Singh A, Ryan CJ, Moses FM, Deuster PA. Dietary patterns, gastrointestinal complaints, and nutrition knowledge of recreational triathletes. Am J Clin Nutr 51: 690–697, 1990. doi: 10.1093/ajcn/51.4.690.

Sampson G, Pugh JN, Morton JP, Areta JL. Carbohydrate for Endurance Athletes in Competition Questionnaire (CEAC-Q): Validation of a Practical and Time-Efficient Tool for Knowledge Assessment. Sport Sci Health 17, 2021. doi: 10/gmq2rx.

Heidel RE. Causality in Statistical Power: Isomorphic Properties of Measurement, Research Design, Effect Size, and Sample Size. Scientifica 2016: 8920418, 2016. doi: 10/gk8w8p.

Jiang D, Pepler D, Yao H. The Effect of Population Heterogeneity on Statistical Power in the Design and Evaluation of Interventions. Int J Behav Dev 34: 473–480, 2010. doi: 10/b9rbvf.

Boisgontier MP, Cheval B. The ANOVA to Mixed Model Transition. Neurosci Biobehav Rev 68: 1004–1005, 2016. doi: 10/f83jzs.

DeBruine L, Krystalli A, Heiss A. faux: Simulation for Factorial Designs [Online]. https://CRAN.R-project.org/package=faux [8 Sep. 2021].

Senn S. Change From Baseline and Analysis of Covariance Revisited. Stat Med 25: 4334–4344, 2006. doi: 10/fdmg6x.

Kassambara A. rstatix: Pipe-Friendly Framework for Basic Statistical Tests [Online]. https://CRAN.R-project.org/package=rstatix [8 Sep. 2021].

Harrison XA, Donaldson L, Correa-Cano ME, Evans J, Fisher DN, Goodwin CED, Robinson BS, Hodgson DJ, Inger R. A Brief Introduction to Mixed Effects Modelling and Multi-Model Inference in Ecology. PeerJ 6: e4794, 2018. doi: 10/gdh936.

McSwiney FT, Doyle L, Plews DJ, Zinn C. Impact Of Ketogenic Diet On Athletes: Current Insights. Open Access J Sports Med 10: 171–183, 2019. doi: 10/ggp3jm.

Coyle EF, Feltner ME, Kautz SA, Hamilton MT, Montain SJ, Baylor AM, Abraham LD, Petrek GW. Physiological and Biomechanical Factors Associated With Elite Endurance Cycling Performance. Med Sci Sports Exerc 23: 93–107, 1991.

Impey SG, Hearris MA, Hammond KM, Bartlett JD, Louis J, Close GL, Morton JP. Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis. Sports Med 48: 1031–1048, 2018. doi: 10/gdwk98.

Hiilloskorpi HK, Pasanen ME, Fogelholm MG, Laukkanen RM, Mänttäri AT. Use of Heart Rate to Predict Energy Expenditure From Low to High Activity Levels. Int J Sports Med 24: 332–336, 2003. doi: 10/fbbg7z.

Quinn TJ, Coons BA. The Talk Test and Its Relationship With the Ventilatory and Lactate Thresholds. J Sports Sci 29: 1175–1182, 2011. doi: 10/bgs275.

Impey SG, Hammond KM, Shepherd SO, Sharples AP, Stewart C, Limb M, Smith K, Philp A, Jeromson S, Hamilton DL, Close GL, Morton JP. Fuel for the Work Required: A Practical Approach to Amalgamating Train-Low Paradigms for Endurance Athletes. Physiol Rep 4: e12803, 2016. doi: 10.14814/phy2.12803.

Posted

2021-10-22