Very low carbohydrate (<5 %), high fat (>70 %) ketogenic diets (VLCKD) diets have previously been shown to have favorable changes in body composition (increased lean mass and decreased fat mass) in obese or overweight individuals. However, the impact of this form of dieting relative to a traditional high carbohydrate diet has not yet been investigated in resistance trained athletes. Therefore the purpose of this study was to investigate the impact of VLCKD verses a traditional western diet on changes in muscle and fat mass.