The Protein Spectrum
How to know if the amount of protein you eat is too much, too little, or just right

By Kelli Rosen

If you're looking for a nutritional hot button, just push the one marked "protein." Some diet experts espouse protein's seemingly limitless virtues; others warn of protein overload and associated high cholesterol. The truth is that too much or too little protein can wreak havoc on your body. If the extent of your daily protein intake consists of a few garbanzo beans tossed on a lunchtime salad, you'll likely end up feeling fatigued at day's end. On the other hand, downing a steak every night will tax your kidneys and leave you sluggish. So it's crucial to know the right amount of protein you need each day to function properly.

Virtually every part of your body—bones, organs, tendons, ligaments and muscles—is made up of protein—amino acid chains that perform various functions depending on each chain's sequence. Protein fights illness by making red blood cells, regulates bodily functions by producing hormones, transports oxygen and forms the building blocks for growth and repair of tissues. Of the 20 amino acids that the body needs to function properly, 11 can be produced internally. The remaining nine, deemed essential amino acids, must be obtained from food.

By The Numbers
According to Roxanne Moore, RD, spokesperson for the American Dietetic Association, the average healthy person weighing 150 pounds needs to consume about 55 grams of protein per day—that's 0.8 grams/kg body weight. (To convert pounds to kilograms, simply divide your weight in pounds by 2.2.) But the numbers quickly change depending on specifics. A 135-pound woman needs about 49 protein grams daily; if she's pregnant, she'll need 10 additional grams, and if she's lactating, she should tack on an extra 12-15 grams daily.

Feel like a nut
Americans tend to overdo it when it comes to protein. Know your body's needs, and consider alternating or substituting traditional protein sources (eggs, meat, milk) with plant-based combinations of whole grains and legumes (nuts, beans, rice). Then you have to consider activity level. The ADA's recommendation of 0.8 protein grams/kg body weight applies to the average sedentary person. A more active person—someone whose job requires movement, or who exercises—needs 1.0-1.2 grams/kg body weight, says Moore. And the truly athletic individual needs 1.2-1.7 grams/kg body weight daily, according to Jackie Berning, PhD, RD, sports nutrition consultant in Colorado Springs, Colorado, whose clients include the Denver Broncos and Cleveland Indians. Protein is especially important for athletes since it's essential for building and maintaining muscles; it also helps repair tissue damage that occurs during training. (For a quick calculation of your own needs, see "Figure It Out.")

"I can immediately look at someone and tell if they lack protein because they've got a grayish complexion," says Nancy Clark, RD, director of nutrition services at SportsMedicine Associates in Brookline, Massachusetts, and author of Nancy Clark's Sports Nutrition Guidebook (Human Kinetics, 1997). Other telltale signs of protein deficiency include hair that falls out easily, fingernails that grow slowly and break often, fatigue and frequent illness due to lowered immunity. Female athletes who are low on protein may also stop menstruating.

So don't sell yourself short. Even if you're not a professional athlete or Olympic medal contender, you're likely to fall somewhere within an athletic spectrum if you work out regularly. Berning says the recreational person who goes to the gym to lift weights and take aerobics classes needs the higher number of protein grams (1.2-1.7 grams/kg body weight) every day as part of a balanced overall diet.

Hold The Meat
What about vegetarians? "It's fine to be a vegetarian athlete," says Clark, "but you must have a heightened awareness as to how much protein you actually need." While animal protein typically has ample amounts of all the essential amino acids, vegetable sources tend to be incomplete. However, by combining different plant-based foods, a vegetarian athlete can readily achieve a balanced protein diet. For example, eating peanut butter on whole-wheat bread or a plate of rice and beans combines the aminos found in legumes and grains, forming a complete protein package. Tofu is also an excellent choice, says Clark, since it contains all of the essential amino acids plus beneficial phytochemicals. Vegans, who do not eat animal products of any kind, should consider consulting with a dietitian to ensure they are meeting all their nutrient requirements, adds Moore.

Living In Excess?
Getting enough protein isn't difficult. In fact, many Americans consume excessive protein, says Lisa Dorfman, RD, author of The Vegetarian Sports Nutrition Guide (Wiley, 2000). "Considering every ounce of animal protein has 7 grams of protein," she explains, "it is not hard for the 170-pound adult to exceed his or her recommended amount with a protein bar for breakfast, a meat or fish-based sandwich for lunch, and a chicken breast or two for dinner."

And too much protein can be costly to your health. When your body has to break down the excess, it increases production of urea, a waste product in urine, so you end up urinating frequently—and running the risk of dehydrating. "You can also eat so much protein that your body stores it as fat," says Berning. "People think they're adding lean muscle when actually they're adding a layer of fat."

Still not sure about how many protein grams you need every day? Clark suggests logging on to the American Dietetic Association's Web site, "You can type in your zip code and find a sports nutritionist in your area who will help you figure out how many grams of protein you need as well as help you construct a diet so you get enough."

Freelance writer Kelli Rosen gets her protein by adding walnuts to oatmeal, chicken or tuna to tossed salads, and peanut butter to just about anything.