Protein Prudence

Lunch is served: a beautiful spinach salad topped with a half-cup of chickpeas, three ounces of chicken, two hard-boiled egg whites and a drizzle of olive oil and vinegar, along with a glass of skim milk. It's a healthful meal that's low in saturated fat and calories, high in fiber and and rich in a variety of nutrients. Eat a salad like this and you can feel virtuous all afternoon.

Or can you? This lunch weighs in with 48 grams of protein—two grams more than a woman is advised to eat in an entire day. Add a cup of low-fat plain yogurt and the meal provides more protein than a man needs in a day.

That's just lunch—eat cereal with milk for breakfast, a handful of nuts for an afternoon snack, and fish or meat for dinner, and you may take in twice the recommended intake of protein.

Millions of Americans have jumped onto the high-protein diet bandwagon, saying that the diets help them lose weight. But is a high-protein diet good for you?

Kidney watch

The short answer is yes—provided your kidneys are in good health. "To the best of our knowledge, you're not damaging your kidneys by eating too much protein," says Johanna Dwyer, professor of medicine at the Tufts University School of Medicine.

When you eat a food that contains protein, the digestive system breaks it down into amino acids and dumps urea, a waste product, into the blood stream. The kidneys remove urea from the blood and dispose of it via the urine. Eating large amounts of protein forces your kidneys to work harder to remove urea from the blood. Kidneys can handle the job if they are healthy. However, if someone with kidney disease eats a high-protein diet, kidney function can worsen as the organs struggle to eliminate large amounts of urea.

More than 20 million Americans have chronic kidney disease, but most don't know it, according to the National Kidney Foundation. An additional 20 million—primarily people with diabetes—have an above-average chance of developing kidney disease. If you have diabetes or any health condition that puts you at risk for kidney disease, you should talk with your doctor about the amount of protein in your diet. Your doctor may want to do a simple blood test that measures kidney function.

If you have healthy kidneys, beefing up the protein in your diet can have some benefits. It takes longer to feel hungry after a protein-rich meal than after a meal that is mainly carbohydrates. And that can translate to weight loss, as anyone who has lost weight on the Atkins diet will tell you.

The bone connection

Protein is connected to bone health, too. In the past, researchers believed excess protein contributed to osteoporosis. "That was the common thinking until recently because high protein intakes lead to higher urinary calcium losses," says Connie Weaver, head of the Department of Foods and Nutrition at Purdue University. Now, researchers know more about how to measure calcium retention in the body, and they have found that high protein intake does not sap calcium from the bones. "In fact, seniors who consume a high-protein diet have fewer hip fractures than those who do not," Weaver says.

Fat company

Protein often gets a bad rap because of the company it keeps. Many protein-rich foods are loaded with artery-clogging saturated fat and cholesterol. However, lean meats, fat-free dairy products, legumes and fish provide protein without a lot of saturated fat.

Even if it is low in saturated fat and cholesterol, however, a high-protein diet lacks nutritional luster if high-protein foods replace the fresh fruits, vegetables and whole grains that supply vitamins, minerals, fiber and other nutrients that protein can't deliver.

A high-protein diet seems safe for healthy people. Although "few studies have rigorously examined the effects of a high-protein intake over long periods of time," says Paul Schmitz, professor of internal medicine at Saint Louis University, "frankly, I am more concerned about the shift to a high consumption of certain saturated and unsaturated fats in the Western diet. A balanced approach to nutrition is best."

From www.eatingwell.com with permission. © 2009 Eating Well Inc.