So if you're planning to work hard, have a smaller snack or eat further ahead of schedule. Avoid fatty foods. Fried foods, doughnuts, pizza, potato chips, etc., all contain lots of fat. Fat leaves your stomach slowly, and may cause nausea and a general bloated feeling during exercise. Avoid high protein meals.
Protein takes a long time to digest.
Protein also tends to increase urine output which can lead to dehydration, especially if you're working out in hot weather. These foods may include bran cereals, fresh fruits with skins and seeds, and most raw vegetables. Generally, eat the foods that sit well with you and digest easily. Some examples might include low-fat yogurt and graham crackers or a banana and skim milk. A little bit of protein is needed regularly throughout the day, but it's the carbohydrates that keep your blood sugar even and your energy levels high.