If consuming a large meal, time is needed for digestion, therefore, it is important to have it 3-4 hours before exercise. If the meal is more of a snack, try 1-2 hours prior. High-carbohydrate, low-fat foods are the best fuel source. Carbohydrate is broken down directly to glucose, the fuel the body will use. Fat will slow digestion, taking longer for the food to be absorbed and leaving you feeling full and uncomfortable.