GU provides athletes with a shot of 100 calories in the form of a patented carbohydrate blend (70%-80% maltodextrin and 30-20% fructose) to deliver high-quality, easily-digested and long-lasting energy for athletes in every sport and at all levels. GU also includes electrolytes to ensure proper hydration, an antioxidant blend to stave off muscle tissue damage and an amino acid blend to delay muscle fatigue. Everything inside each packet of GU is engineered to do one simple thing: provide your body with the essential requirements it needs to keep going for miles and miles and hours and hours. It goes down easy, and it goes to work fast so you don't have to slow down. 100 calories is an ideal serving size to suck down 15 minutes before training or racing in order to top off your electrolyte and glucose stores, followed by one every 30-45 minutes along the way, washed down with a few sips of fluid. For optimum results, always drink at least 24-30 ounces of fluid per hour during training and racing. Exact GU intake depends on the intensity of your pursuit and your body weight and fitness level. The fitter you are and the more efficient your metabolism, the more GU you can eat each hour, up to approximately 340 calories every 60 minutes.