Ketogenic diets have long been used in the strength training world. Bodybuilders, powerlifters and wrestlers have all made use of ketogenic diets. As posted here, their effects on diabetics and epileptics are being analyzed. Their effects on overall performance should be analyzed. Paoli et al 2012 set out to analyze this.
9 elite male gymnasts from Italy were recruited and placed on a very low carbohydrate ketogenic diet. Tests included hanging leg raises, push ups, parallel bar dips, pull ups, squats jumps, countermovement jumps and 30 secs of continuous jumping. Keep in mind, these athletes average training volume was 30 hours/week.
The diet provided was 54.8% fat, 40.7% protein and 4.5% carbohydrate with all vitamins and minerals accounted for to ensure proper nutrition.
Performance wise, the athletes showed no difference from the start and end of the study. Yet they lost an average 1.6kg of fat mass over the 30 day period.
This indicates that many athletes concerned either about aesthetics or weight categories can use a properly controlled ketogenic diet and after adaptation, perform at their normal levels of function while losing weight through macronutrient manipulation.