The Effects of a Six-Week Ketogenic Diet on CrossFit Performance Parameters: A Pilot Study

Background: CrossFit is a popular high-intensity functional training method. Despite the importance of muscle glycogen in fueling such high-intensity efforts, research exploring the use of a ketogenic diet in CrossFit practitioners is limited. Objectives: To conduct an experimental trial examining the effects of a 6-week ketogenic diet on CrossFit performance parameters. Methods: Eight men and seven women (N = 15; 30.2 ± 4.11 years) were recruited for this experimental study design and were randomly assigned to either the ketogenic diet (KD; n = 8) or the control group (CON; n = 7) for 6 weeks. Several measures of anaerobic performance were assessed at baseline and after 6 weeks utilizing the following series of standardized exercise tests: timed 500 m row, Wingate Anaerobic Test, and 3-repetition maximum (3-RM) deadlift. Aerobic capacity was also assessed by measuring VO2peak. In addition, body composition was assessed via BodPod. Results: Multiple 2 X 2 mixed factorial analyses of variance were performed for measures of body composition and aerobic and anaerobic performance variables. No significant differences in body composition (p 0.05), anaerobic performance (p 0.05), or aerobic performance (p 0.05) were observed between groups. Conclusion: A 6-week ad libitum KD had no effect on exercise performance or body composition in CrossFit practitioners. Our findings demonstrate that a KD does not impair CrossFit performance, which may be of interest to those considering a KD when participating in CrossFit.