With intense exercise your body shifts 80 percent of its blood supply to the muscles in use. This shift deprives the stomach of the blood needed to digest food. This slows digestion and may cause an uncomfortable feeling in the stomach because of undigested food that is still present. A meal that is high in calories will take longer to digest than a lighter snack. It is suggested a three to four hour delay between high calorie meals and intense exercise.

Eat foods that are familiar to you and meals that are reasonably high in carbohydrate and low in fat (avoid high fat sauces on pasta and fast food). Carbohydrates will help keep the energy level high.

Drink adequate amounts of fluid (avoid dairy). The American College of Sports Medicine recommends 17 ounces of fluid two hours before exercise, as well as enough fluid during exercise to replace the water lost through perspiration. A rule of thumb is to drink enough water to urinate clear prior to performance. For the first hour of aerobic exercise use water only. Use electro-light replacement drinks after the first hour of exercising.

Athletes are recommended to wait 2-3 hours after a small meal and 1-2 hours after a blended or liquid meal. There are energy “boost” supplements such as PowerGel by PowerBar that are consumed by the athlete immediately before and during exercise. They can be easily digested and they provide energy during long-term events.