Ketogenic Diet: from the Historical Records to Use in Elite Athletes.

To review the available literature/evidence on low carbohydrate/high fat (LCHF) and low carbohydrate ketogenic (LCKD) diets' effects on human athletic performance and to provide a brief review of the physiology and history of energy systems of exercise. Multiple studies have been conducted in an attempt to answer this question, many within the last 3-5 years. Studies are heterogenous in design, intervention, and outcome measures. Current available data show that LCHF and LCKD do not significantly enhance or impair performance in endurance or strength activities. However, there is a trend towards improved body composition (greater percent lean body mass) across multiple studies. While this may not translate to enhanced performance in the primarily laboratory conditions in the reviewed studies, there could be a benefit in sports in which an athlete's strength-to-weight ratio is a significant determinant of outcome.