Her Sports Magazine

We're mad about protein, and many of us are eating too much. Find out how to avoid going overboard and which sources will leave you in fighting shape.

By Kimberly A. Tessmer, R.D.

You know high-protein diets lack essential nutrients, and that carb restriction can be an athlete's death knell. But protein is vital to everything from muscle building and repair to metabolism and hair growth, and needs careful consideration in an active woman's diet. The question, then, is how much do you need? And what sources are best?

The theory adopted by many athletes is that more protein equals more muscle. In truth, extra protein offers no added performance benefits, and may actually be harmful to the kidneys and weaken the bones.

     In proper quantities, however, protein is a powerhouse nutrient. It's found in every cell of the body, and is responsible for helping build and repair body tissues, regulating digestion and metabolism, producing enzymes, replacing red blood cells, growing hair and fingernails, creating hormones and other body chemicals, and boosting the immune system.

Too Much of a Good Thing?

     When you eat too much protein—as studies have shown most Americans do—it is not stored as protein but rather used as fuel or stored as fat. If you're consuming adequate calories, protein will likely end up as fat, since the body will select carbohydrates as an energy source first and foremost.

    Consuming too much protein also increases urination (since protein pulls water from the body to help excrete and dilute urea, a waste product formed when protein turns to fat), increasing the chance of dehydration, which can greatly hinder athletic performance.

     Excess protein also places stress on the kidneys, and can increase the body's excretion of calcium, creating increased risk for osteoporosis.

    Since animal foods are most people's main source of protein, diets high in protein also tend to be higher in heart-damaging saturated fat and cholesterol, placing your health at further risk.

How Much Do You Need?

    The key is to consume the amount of protein your body needs for your level of physical activity. The recommended intake for protein can generally be met through diet alone. In fact, most people already eat more protein than their body needs. If calorie intake is adequate and your diet is balanced, protein and/or amino acid supplements are not necessary.

To determine your protein needs, simply multiply your weight in pounds by one of the following:

SEDENTARY ADULT (not currently exercising) = 0.4 grams
RECREATIONAL EXERCISER (exercising regularly at least two times per week) = 0.5 - 0.75 grams. The upper end of the range is recommended for those who participate in strength and/or speed training.
COMPETITIVE ATHLETE (training regularly and competing in races or endurance events) = 0.6 - 0.9 grams

For example, for a 150-pound recreational exerciser the formula is 150 pounds x 0.5 grams = 75 grams of protein daily.

Good Choices

Select from the following foods to get the best sources of protein in the right amounts.

8 GRAMS OF PROTEIN: 1 cup of nonfat/low-fat milk or 6 ounces of low-fat yogurt

7 GRAMS: 1 ounce of very lean or lean meat, 1 ounce of fish, 2 egg whites, 1 whole egg, 1 ounce of low-fat cheese, 1/4 cup low-fat cottage cheese, 2 tablespoons reduced-fat peanut butter, 3 ounces tofu or 1/2 cup legumes

3 GRAMS: 1 slice of whole wheat bread, 1/2 cup whole grain cereal, one 6-inch tortilla, 1/3 cup pasta, 1/3 cup brown rice, one 3-ounce potato or 1/2 cup yams

2 GRAMS: 1/2 cup cooked vegetables or 1 cup raw vegetables

Based on Exchange Lists for Weight Management, 2003 (American Dietetic Association and the American Diabetes Association)

Which Protein Sources Are Best?

     The body uses 20 amino acids in different combinations to make up the thousands of different proteins your body needs. Of these 20 amino acids, there are nine your body cannot make. These are called essential amino acids and must be supplied by diet.

     Foods such as meat, poultry, fish, eggs, milk, cheese, yogurt and soy products provide all nine of these essential amino acids and are considered complete proteins. Soy is actually the only plant food that contains all nine of the essential amino acids and is considered a complete protein.

     Legumes (beans and peas), seeds and nuts supply all but a few essential proteins, and grain products and many vegetables also supply protein but can be lacking in several essential amino acids. These foods are considered incomplete proteins.

     For the body to make its required proteins, your food choices need to supply sufficient amounts of the essential amino acids. As long as your meals and snacks provide a variety of plant foods, lean animal foods, and your calorie needs are met, you will acquire all the amino acids your body needs.

     Even if you are vegetarian or vegan, you can still get plenty of essential amino acids by eating soy and a variety of plant foods.

     To avoid saturated fat and high levels of LDL cholesterol, stick to lean and extra lean cuts of meat such as skinless chicken and turkey breast, pork loin, lean ground beef, lean ground turkey breast, beef sirloin and tenderloin.

     Include fish like tuna (packed in water) or that is grilled or broiled, fat-free or low-fat dairy products such as milk, yogurt and cheese, and limit egg yolks to three per week. Better yet, opt for egg whites, where egg protein is concentrated.

     Incorporate a variety of plant foods in your daily diet as a way to help provide protein without the saturated fat and cholesterol. In addition, plant foods provide a good source of fiber and essential vitamins and minerals.

The Bottom Line

     Your body's first priority is to meet its energy or calorie needs. If your body does not get enough carbohydrates and fat for energy, it will begin to break down protein from food or from body tissues such as the muscles to get what it needs. Consuming enough calories from carbohydrates and fat each day will spare protein for the work it does best.

     Protein is critical for optimal health but going overboard can do your body more harm than good. Stick to the formula on page 59 and opt for the healthiest varieties to keep performing at your best.

Kimberly A. Tessmer is a registered dietician and owner of Nutrition Focus, specializing in nutrition, health and weight loss. Her upcoming book The Everything Pregnancy Nutrition Book will be released by Adams Media in January 2005. She is also author of The Everything Nutrition Book and Gluten-Free for a Healthy Life. For more information visit www.nutrifocus.net.

Article appeared in the Mar/Apr 2005 Issue.