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. 2018 Jan 9;6(1):1.
doi: 10.3390/sports6010001.

The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study

Wesley C Kephart  1   2 , Coree D Pledge  3 , Paul A Roberson  4 , Petey W Mumford  5 , Matthew A Romero  6 , Christopher B Mobley  7 , Jeffrey S Martin  8   9 , Kaelin C Young  10   11 , Ryan P Lowery  12 , Jacob M Wilson  13 , Kevin W Huggins  14 , Michael D Roberts  15   16
Affiliations

The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study

Wesley C Kephart et al. Sports (Basel). .

Abstract

Adopting low carbohydrate, ketogenic diets remains a controversial issue for individuals who resistance train given that this form of dieting has been speculated to reduce skeletal muscle glycogen levels and stifle muscle anabolism. We sought to characterize the effects of a 12-week ketogenic diet (KD) on body composition, metabolic, and performance parameters in participants who trained recreationally at a local CrossFit facility. Twelve participants (nine males and three females, 31 ± 2 years of age, 80.3 ± 5.1 kg body mass, 22.9 ± 2.3% body fat, 1.37 back squat: body mass ratio) were divided into a control group (CTL; n = 5) and a KD group (n = 7). KD participants were given dietary guidelines to follow over 12 weeks while CTL participants were instructed to continue their normal diet throughout the study, and all participants continued their CrossFit training routine for 12 weeks. Pre, 2.5-week, and 12-week anaerobic performance tests were conducted, and pre- and 12-week tests were performed for body composition using dual X-ray absorptiometry (DXA) and ultrasound, resting energy expenditure (REE), blood-serum health markers, and aerobic capacity. Additionally, blood beta hydroxybutyrate (BHB) levels were measured weekly. Blood BHB levels were 2.8- to 9.5-fold higher in KD versus CTL throughout confirming a state of nutritional ketosis. DXA fat mass decreased by 12.4% in KD (p = 0.053). DXA total lean body mass changes were not different between groups, although DXA dual-leg lean mass decreased in the KD group by 1.4% (p = 0.068), and vastus lateralis thickness values decreased in the KD group by ~8% (p = 0.065). Changes in fasting glucose, HDL cholesterol, and triglycerides were similar between groups, although LDL cholesterol increased ~35% in KD (p = 0.048). Between-group changes in REE, one-repetition maximum (1-RM) back squat, 400 m run times, and VO2peak were similar between groups. While our n-sizes were limited, these preliminary data suggest that adopting a ketogenic diet causes marked reductions in whole-body adiposity while not impacting performance measures in recreationally-trained CrossFit trainees. Whether decrements in dual-leg muscle mass and vastus lateralis thickness in KD participants were due to fluid shifts remain unresolved, and increased LDL-C in these individuals warrants further investigation.

Keywords: body composition; ketogenic diet; power; strength.

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Conflict of interest statement

Ryan P. Lowery and Jacob M. Wilson are actively involved in ketogenic salt patents, and have authored a for-profit book describing ketogenic diets (). None of the other authors have conflicts of interest in publishing these data. The only costs herein were the serum analyses, which were funded through residual funds provided to Michael D. Roberts through a prior grant awarded to him by the Applied Sports Performance Institute (ASPI). No salaries or royalties were received from ASPI for this project.

Figures

Figure 1
Figure 1
Study design. This figure depicts the 12-week dietary intervention. Notably, all participants continued their normal workout routine at the local CrossFit training facility during the study. Abbreviations: KD, ketogenic diet; CTL, control diet; 1-RM, one repetition maximum.
Figure 2
Figure 2
Weekly blood ketone and body composition effects prior to and 12 weeks following the study. Weekly blood beta-hydroxybutyrate (BHB) levels are presented in panel (a); DXA body mass, DXA fat mass, DXA lean body mass, DXA dual-arm lean mass, DXA dual-leg lean mass, and vastus lateralis thickness (assessed via ultrasound) are presented in panels (b–g); Data in panel (a) are presented as means ±SE; Bar graph data in panels (b–g) are presented as group means accompanied by individual participant values, and means (±SE) values are indicated at the bottom portion of each bar. Abbreviations: KD, ketogenic diet; CTL, control diet; T1, baseline testing; T3, 12-week post-testing. Symbols: * indicates between-group difference in blood BHB (p < 0.05).
Figure 3
Figure 3
Effects of the intervention on resting energy expenditure and respiratory quotient values. Resting energy expenditure (REE) and resting respiratory quotient (RQ) values are presented in panels (a,b). Data are presented as group means accompanied by individual participant values, and means (±SE) values are indicated at the bottom portion of each bar. Abbreviations: KD, ketogenic diet; CTL, control diet; T1, baseline testing; T3, 12-week post-testing.
Figure 4
Figure 4
Effects of the intervention on strength, anaerobic, and aerobic performance metrics. One-repetition maximum (1-RM) squat, 1-RM power clean, maximum pushup repetitions, 400-m run time, and VO2peak values (assessed with a graded treadmill test and indirect calorimetry) are presented in panels (a–e). Data are presented as group means accompanied by individual participant values, and means (±SE) values are indicated at the bottom portion of each bar. Abbreviations: KD, ketogenic diet; CTL, control diet; T1, baseline testing; T2, 2.5-week testing; T3, 12-week post-testing.
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References

    1. Longland T.M., Oikawa S.Y., Mitchell C.J., Devries M.C., Phillips S.M. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: A randomized trial. Am. J. Clin. Nutr. 2016;103:738–746. doi: 10.3945/ajcn.115.119339. - DOI - PubMed
    1. Antonio J., Peacock C.A., Ellerbroek A., Fromhoff B., Silver T. The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. J. Int. Soc. Sports Nutr. 2014;11:19. doi: 10.1186/1550-2783-11-19. - DOI - PMC - PubMed
    1. Antonio J., Ellerbroek A., Silver T., Orris S., Scheiner M., Gonzalez A., Peacock C.A. A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women—A follow-up investigation. J. Int. Soc. Sports Nutr. 2015;12:39. doi: 10.1186/s12970-015-0100-0. - DOI - PMC - PubMed
    1. Campbell B., Kreider R.B., Ziegenfuss T., La Bounty P., Roberts M., Burke D., Landis J., Lopez H., Antonio J., Taylor L.W., et al. International society of sports nutrition position stand: Protein and exercise. J. Int. Soc. Sports Nutr. 2007;4:8. doi: 10.1186/1550-2783-4-8. - DOI - PMC - PubMed
    1. Roberts M.D., Holland A.M., Kephart W.C., Mobley C.B., Mumford P.W., Lowery R.P., Fox C.D., McCloskey A.E., Shake J.J., Mesquita P., et al. A putative low-carbohydrate ketogenic diet elicits mild nutritional ketosis but does not impair the acute or chronic hypertrophic responses to resistance exercise in rodents. J. Appl. Physiol. 2015;120:1173–1185. doi: 10.1152/japplphysiol.00837.2015. - DOI - PubMed

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