|Friday, March 24
For the recreational or competitive athlete, the body must be fueled optimally to exercise effectively. To maintain or improve strength, speed and stamina, one must consume adequate amounts of protein, carbohydrate and fat.
Carbohydrate-containing foods have always been the staple of a sports diet, but many athletes consume less than optimal amounts. Carbohydrate is the primary energy source for high intensity, maximal-outburst activity, and a significant early fuel source for endurance exercise. Consuming adequate amounts of carbohydrate maintains usual training intensity and promotes rapid recovery.
Carbohydrate containing foods should be eaten at each meal and also before, during and after exercise. At meals, carbohydrates should take up about two-thirds of the plate. Pre-exercise carbohydrates stimulate muscle glycogen storage and may help delay fatigue. Carbohydrates consumed during exercise that lasts more than 60 minutes help the body maintain blood glucose availability late in exercise. Post-exercise carbohydrates help improve muscle glycogen storage, especially within 30 minutes after the activity. The body can store twice as much muscle glycogen after consuming sucrose or glucose than after fructose.
Weight (in pounds) x 3 or 4 = number of grams of carbohydrate per day
Protein is not the body's preferred fuel source during exercise, but it has a role to play in muscle growth and repair, and in boosting the immune system. Exercise can promote muscle protein loss due to reduced protein synthesis, increased protein breakdown and protein losses in urine and sweat. Some athletes tend to overdo on protein, while others barely meet their needs. Food is the easiest, most effective and least costly way to meet protein needs. If it seems difficult to meet the protein requirements, a scoop of nonfat dry milk powder added to milk, sauces or soups, or a sports bar that contains protein can help.
This nutrient has gotten a bad reputation for increasing weight and disease risks. Fat is the primary energy substrate for low intensity and moderate exercise, and consuming too little fat may limit the duration and quality of exercise. Fat is an energy dense nutrient, providing nine calories per gram. It is a good calorie source for active individuals. Although a diet high in animal fats is not the goal, including nuts or olive oil in the diet daily, and eating fatty fish, such as salmon or tuna, may benefit the athlete's health and help prevent injury.
Too little fat may limit performance by affecting intramuscular triglycerides, as well as decreasing serum testosterone in male athletes. A little bit of fat prior to exercise will probably digest better than a cheeseburger and fries. Although some researchers are investigating fat loading prior to exercise, the current advice is to eat a mixed meal of carbohydrate, protein and some fat.
Desirable weight (in pounds) x 0.45 = number of grams of fat per day
The bottom line
Leslie Bonci, M.P.H., R.D., is the director of Sports Nutrition for the Department of Orthopaedic Surgery at the University of Pittsburgh Medical Center Health System. She is the nutrition consultant to the University of Pittsburgh Athletics Department, the Pittsburgh Steelers, the Pittsburgh Riverhounds and the Pittsburgh Ballet Theatre. Bonci is also a national spokesperson for the American Dietetic Association.