A study was conducted to evaluate the effects of a 12-week ketogenic diet (KD) on body composition, metabolic, and performance parameters in individuals who trained recreationally at a local CrossFit facility. The results showed that the KD group experienced a significant reduction in body mass, body fat percentage, and body mass index, with no significant changes in muscle mass. Additionally, the KD group demonstrated significant improvements in endurance exercise performance, with no significant changes in strength performance.