Eating and Athletic Performance

Dr. Richard Honaker

Eating and Athletic Performance

altThe 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 also would 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 amounts 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-excise 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.
Remember when carbohydrate-loading diets were popular? These diets aimed to increase muscle glycogen levels in order to supply energy during prolonged exertion.  Exhaustion following prolonged activity may result from a depletion of glycogen (stored sugar).  In carbohydrate loading, the idea was to reduce the glycogen in muscles with a low carbohydrate diet for several days and heavy workouts.  One then “loaded” with carbohydrates and reduced exercise for several days before competition.  The body supposedly responded to this method by storing glycogen, which could be used as fuel to delay the onset of fatigue during competition. This method was not altogether safe, as it often required the body to depend upon protein instead of carbohydrates for energy.  It may also have resulted 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 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. 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.

By International Racquetball Tour (IRT) contributor, Richard A. Honaker, M.D., F.A.A.F.P. who is a Family Practice Physician in Carrollton, Texas, which is a Dallas suburb. He is an avid racquetball player.