Abstract

Background: The purpose of this research was to examine the effects of a 6-week LCKD and CrossFit program on body composition and performance. Methods: Twenty-seven non-elite CrossFit subjects (mean ± SD age = 34.58 ± 9.26 years) were randomly assigned to a LCKD (males, n = 3; females, n = 9) or control (CON) (males, n = 2; females, n = 13) group. LCKD was instructed to consume an ad libitum diet and restrict carbohydrate intake to less than 50 grams per day and CON maintained usual dietary intake. All subjects participated in four CrossFit training sessions per week during the 6 weeks. Results: Compared to CON group, the LCKD group significantly decreased weight (0.18 ± 1.30, -3.45 ± 2.18 kg), BMI (0.07 ± 0.43, -1.13 ± 0.70 kg/m2), percent body fat (% BF) (0.01 ± 1.21, -2.60 ± 2.14 %), and fat mass (FM) (0.06 ± 1.12, -2.83 ± 1.77 kg), respectively. There was no significant difference in lean body mass (LBM) change between or within groups. We found no significant difference in total performance time change between groups; however, both groups significantly decreased total performance time (CON: -41.20 ± 43.17 sec.; LCKD: -55.08 ± 44.29 sec). Carbohydrate intake was significantly lower (11.4 ± 5.6%, 40.06 ± 6.81%) and fat intake was significantly higher (62.88 ± 4.19%, 38.38 ± 4.18%) in LCKD compared to CON, respectively. Conclusions: Our data show that a LCKD combined with 6 weeks of CrossFit training can lead to significant decreases in %BF, FM, weight, and BMI while maintaining LBM and improving performance.

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