This book helps athletes in managing nutrition and choosing supplements that improve athletic performance, based on strong scientific evidence and in complete safety. It covers all the main types of physical activity, from the gym to cycling, from running to crossfit, considering also the needs of special categories of sportsmen. Specific nutritional approaches, such as the ketogenic diet and intermittent fasting, are also described. 86 data sheets report the features and properties supplements that allow an optimal performance. Each supplement is assigned a score, to allow the reader to evaluate its effectiveness in improving the parameters that influence athletic performance (strength, resistant strength, mass, endurance, weight loss, concentration, recovery).