International society of sports nutrition position stand: ketogenic diets

This position stand provides a review of ketogenic diets in healthy exercising adults, focused on exercise performance and body composition, and does not address exogenous ketone supplements. It defines nutritional ketosis as serum ketones above 0.5 mM, with a broad guideline of under 50 g of carbohydrate per day, and states it should not be confused with ketoacidosis. It reports that a ketogenic diet has largely neutral or detrimental effects on athletic performance compared with higher carbohydrate diets, despite fat oxidation of about 1.5 g/min, and that all studies in elite athletes showed a performance decrement over six weeks or less. Effects on maximal strength are similar to higher carbohydrate diets, and there is insufficient evidence to determine whether effects differ between males and females.