Carbohydrate loading is an endurance-sport strategy in which athletes first deplete then super-compensate muscle glycogen before an event, aiming to extend stamina. The classic protocol involved several days of hard training on low carbohydrate intake followed by three days of high carbohydrate eating with tapered training; modern versions simply raise carbohydrate intake to 8 to 12 grams per kilogram of body weight in the days before competition. Since glycogen binds water, athletes gain weight during loading. The practice is controversial: it can cause digestive discomfort, and benefits are clearest for events lasting over 90 minutes. Sports dietitians individualise the approach.