The interval between eating and exercise may play an important role in one's performance. Vigorous exercise before a meal will raise your metabolic rate and thereby burn more calories. This elevated metabolic rate may last for as long as 24 hours. Exercise would also deplete the storage form of glucose (sugar), known as glycogen. This means that further glucose which is taken in during the meal can be stored as glycogen and not as fats. Also, the outpouring of adrenaline, growth hormone, and cortisol which exercise causes may reduce hunger.
Vigorous and intense exercise shortly after a meal may cause problems related to shunting of blood away from the digestive tract towards the muscles working during exercise. The subsequent delay in digestion is harmful to the body's processes. This is not to say that a pre-exercise meal is wrong. In fact, fasting for long periods prior to exercise may reduce the glycogen stores to a point that prolonged competition can be impaired as nutrients are running low. One should ideally eat at least two and one-half to three hours prior to exercise to allow time for the stomach to empty into the intestines, and for the digestive process to be well under way.
Excessively large amount of sugars and carbohydrates should not be taken in during the pre-exercise meal. Approximately one to four grams of carbohydrate per kilogram of body weight should be taken one to four hours prior to prolonged exercise. The closer the meal is to exercise, the lower the carbohydrate intake should be. One gram per kilogram is appropriate within an hour of exercise, but four grams per kilogram is safe if eaten four hours prior to vigorous exercise.
Best foods for pre-exercise meals are easily digestible and not heavy on fat or calories. Yogurt without fat, milk (1%) fruit, crackers, breads, and small amounts of meat without high fat contents are good ideas. High carbohydrate beverages include GatorLode, Exceed High Carbohydrate Source, and Carboplex. These drinks should not be used during exercise, however, as their carbohydrate content is very high.
Although vigorous exercise directly after eating is not advisable, likewise sedentary life-style directly after eating is also inadvisable. Post meal walking aids digestion and burns excess calories.
Carbohydrates loading diets have been popular recently. These diets aim to increase muscle glycogen levels in order to supply energy during prolonged exception. Exhaustion following prolonged activity may result from a depletion of glycogen (stored sugar). In carbohydrate loading, the idea is to reduce the glycogen in muscles with a low carbohydrate diet for several days and heavy workouts. One then "loads" with carbohydrates and reduces exercise for several days before competition. The body supposedly responds to this method by storing glycogen which can be used as fuel to delay the onset of fatigue during competition. This method is not altogether safe, as it often requires the body to depend upon protein instead of carbohydrates for energy. It may also result in dizziness and weakness during the training phase, and nausea and vomiting during the return to the high carbohydrate diet, known as the loading phase. The best approach is not to be overly enthusiastic on this type of dieting. Eat a balanced diet with the appropriate amounts of carbohydrates, fats, and protein. Vegetables, cereals, pastas and whole wheat bread are good nutritional forms of energy.
Reproduced with permission from Killshot Magazine