When exercising it is important to fuel your body right so you can have the energy you need to perform well.
Since your body relies mainly on carbohydrates for fuel, eat a small meal or snack that includes a mix of simple and complex carbohydrates. This is particularly important if you exercise in the morning. Examples include a granola bar, bagel, or small bowl of cereal or oatmeal. Try to eat 30-60 minutes before exercising so your food has time to settle.
After exercise it is important to refuel quickly. Try to eat something within an hour of exercising. A post-exercise meal or snack should include carbohydrates and protein. Carbohydrates will help replace your energy stores. Protein is necessary to help rebuild and repair muscle that was worked during an exercise session.