Thursday, November 4

Protein nutrition for athletes
By Sharon Howard, R.D., M.S., C.D.E. FADA Why is protein important for athletes?

Protein is essential to the human body for growth and repair of tissue. Beyond making muscle, protein helps athletes to maintain blood, to keep hormones working and to fight off disease by enriching the immune system. Protein is made up of chains of amino acids, some of which the body cannot manufacture. Athletes who get too little protein may find that their hair falls out easily, and females may develop amenorrhea. Some athletes surprisingly get too little protein; perhaps they are vegetarian, perhaps they focus only on increasing carbohydrates as fuel or perhaps they cannot find the time or energy to create balanced meals with protein. A high-carbohydrate diet that is low in protein can still cause fatigue and poor performance. Other athletes may overdo protein intake at the expense of a balanced diet, or rely on amino acid supplements of questionable value to increase protein intake that basic diet improvements could provide.

How much protein should an athlete consume?

The normal amount of protein recommended for sedentary people is 0.8 grams of protein per kilogram of body weight per day. (Take your weight in pounds and divide by 2.2 to get your weight in kilograms.) In athletes, several factors determine the amount of protein needed -- duration and intensity of exercise, degree of training and current energy and protein intake of the diet.

Athletes who train hard need more protein than the average individual. In one study, men who did aerobic exercise regularly (biking, running, swimming) needed additional protein 50 percent over their RDA. By measuring nitrogen balance, a technique used to determine if more protein is lost from the body than taken in by the diet, researchers found these active men needed extra protein to cover the cost of exercise. The additional amount was about 27 grams, the same as a 3-ounce chicken breast, two and a half cups of milk or a can of tuna. This makes it unnecessary to purchase expensive amino acid drinks. The amount of amino acids in pills and drinks should be compared to what 1 ounce of meat, fish or chicken provides. An ounce of food protein provides 7 grams of protein, or 7000 milligrams of amino acids.

The explanation for this increased protein comes from studies showing that amino acids are also broken down for energy in exercising muscles. When glycogen stores get low during an exercise session, the body breaks down some fat and a little bit of muscle. During post-exercise recovery, rebuilding with protein is necessary.

Strength athletes need 1.4 to 1.8 grams of protein per kilogram of body weight per day; this extra protein goes to increase muscle weight. Runners and other endurance athletes also need more protein because on long workouts their muscles burn some protein. These athletes need 1.2 to 1.4 grams of protein per kilogram of body weight per day. Because endurance athletes weigh less than strength trainers, the amount of protein needed per day is less. For example, a 200-pound bodybuilder (91 kilograms) needs 127 to 163 grams of protein; on the other hand, a 150-pound runner (68 kilograms) may need 82 to 95 grams of protein. The protein goal is about 12 to 20 percent of total calorie intake. Moderate exercisers need additional 10 percent protein above the RDA, and athletes in training may need 25 to 50 percent more than the RDA.

Protein is required on a daily basis, but too much can be a problem. Extra calories, no matter what the source, can be converted to stored body fat and protein beyond the recommendations must be processed by the kidneys and liver to rid the body of unwanted nitrogen byproducts. The kidneys have to flush out toxins in urine, so athletes getting an excess of protein could risk dehydration. Also, studies show that excessive protein may cause the loss of calcium in urine, which puts women at risk for osteoporosis.

How do grams of protein convert to food?

An ounce of meat, fish, chicken, egg or cheese contains roughly 7 grams of protein. So, an 8-ounce steak provides 56 grams of protein. Every serving of bread, pasta and cereal provides 3 grams of protein. Take a look at this Protein Counter to see how easy it is to get your goal amount. Increasing the portion size quickly improves the protein count.


Food Serving Grams of Protein Calories
1 egg white white of 1 egg 3.5 17
1 egg 1 large 6 80
lean ground beef, cooked 3 ounces 21 214
roasted chicken breast without skin 3 ounces 26 150
broiled top round beef 3 ounces 26 180
salmon 3 ounces 23 157
cheddar cheese 1 ounce 7 110
low-fat yogurt 1 cup 10 160 (sugared)
skim milk 1 cup 8 86
tuna 3 ounces 25 111
baked beans 1 cup 14 175
lentils 1 cup 18 231
pasta 1 cup 5 160
bread 2 slices 6 160
tofu 1/2 cup 10 94
cottage cheese 1/2 cup 14 82

Are amino acid supplements necessary?

The trend to supplement the diet with protein powders and liquids is prevalent in athletes, particularly in bodybuilders. Athletes should know their protein goals, how much they derive from their diets, and turn them to complete protein supplements if necessary. Many products containing casein and whey protein or soy protein are available. Shakes and energy bars can be convenient for athletes who spend many hours training. A protein shake with milk and fruit is an easy way to add a nutritious high-protein snack to the diet. Some energy bars offer 14 to 25 grams of protein in a single serving. Although studies evaluating effectiveness and safety are lacking, athletes should be careful of expensive isolated amino acid supplementation because of potential toxicity.

A word about fat....

Most athletes need about 25 to 30 percent of their calories from fat. Those who are trying to lose weight can reduce fat to no less than 20 percent of their total calories. Fat is a necessary fuel to spare the carbohydrates for glycogen storage and muscle energy and to spare protein for its muscle repair and building.

Of course, the best fats are the heart healthy fats. Select lean meats and low-fat dairy fats to avoid saturated fats, and use olive oil or canola oil in dressings and cooking to get more monounsaturated fats. Omega-3 fatty acids from fish are especially beneficial.

The search for the optimal diet for exercise continues. Athletes should have their current calorie and protein intake assessed before they make any changes to their diets. Since nutritional advice can be offered from sources as varied as successful athletes, self-proclaimed nutritionists, supplement salespersons and trained sports nutrition specialists, athletes would be wise to search for professional assistance.

The information, including opinions and recommendations, contained in this website is for educational purposes only. Such information is not intended to be a substitute for professional medical advice, diagnosis or treatment. No one should act upon any information provided in this website without first seeking medical advice from a qualified medical physician.

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