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Sports (Basel). 2018 Jan 9;6(1). pii: E1. 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.

Author information

1
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. kephartw@uww.edu.
2
Department of Health, Physical Education, Recreation and Coaching, University of Wisconsin-Whitewater, Whitewater, WI 53190, USA. kephartw@uww.edu.
3
Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, AL 36849, USA. cdp0017@auburn.edu.
4
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. par0021@auburn.edu.
5
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. pwm0009@auburn.edu.
6
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. mzr0049@auburn.edu.
7
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. moblecb@auburn.edu.
8
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. jmartin@auburn.vcom.edu.
9
Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL 36830, USA. jmartin@auburn.vcom.edu.
10
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. kyoung@auburn.vcom.edu.
11
Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL 36830, USA. kyoung@auburn.vcom.edu.
12
Applied Sports Performance Institute, Tampa, FL 33607, USA. rlowery@theaspi.com.
13
Applied Sports Performance Institute, Tampa, FL 33607, USA. jwilson@theaspi.com.
14
Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, AL 36849, USA. huggikw@auburn.edu.
15
School of Kinesiology, Auburn University, Auburn, AL 36849, USA. mdr0024@auburn.edu.
16
Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL 36830, USA. mdr0024@auburn.edu.

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

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.

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