Intermittent fasting and the ketogenic diet are two powerful tools with great benefits at the intestinal, brain level, weight loss, immunology, metabolic damage, and so on. But when doing sports we have the following doubts ... What to eat before, what to eat later? Am I going to lose muscle mass? How to accelerate fat loss? How to gain muscle? How to introduce sport on an empty stomach depending on the context 12/12, 16/8, 20/4 23/1? or if I train strength sports, soccer, athletics, high intensity or whatever your sport is. In this book I will explain all that and the benefits, errors and supplementation in intermittent fasting and the ketogenic diet.