The (Short-term) Case for High Protein Diets

While no one knows the effect of eating a high-protein diet over the long-term, the diet appears to be safe and effective for up to six months.

Frank Hu, MD, PhD, assistant professor in the Department of Nutrition at Harvard University School of Public Health in Boston, asked a student to review published studies on high-protein diets and try to answer these four important questions:

• Do high protein diets increase fat burning in the body?
• Do they increase satiety (the sense of being "full" or "satisfied" after a meal)
• Do they decrease subsequent energy (calorie) intake by the body? and
• Do they lead to weight loss?

For the most part, says Hu, the answers are "yes." Protein can be converted by the body into glucose for energy, but it takes twice as much effort as converting carbohydrates or fats into glucose. The extra effort translates into fewer calories available, Hu said at a recent symposium on the science of obesity.

When it comes to feeling full, the clinical studies consistently showed that high protein diets increase satiety and decrease hunger compared with high fat or high carbohydrate diets. In addition, most, but not all of the studies reviewed showed that most people on high protein diets took in about 10% less energy (roughly 200 calories) per day, which could account for at least some of the weight loss seen with this type of diet.

"There is some evidence that high protein diets induce great fat loss," Hu told the symposium audience. On average, high protein diets produced an average weight loss that was about 4.5 lbs greater than that achieved on other diets after six months.

"Most of the studies show results for up to 6 months, but after 6 months they begin to lose effectiveness, either because people do not adhere to this diet very well in the long term, or because they get used to this diet biologically," Hu tells WebMD. "So in the long term the high-protein diets tend to lose their ability to maintain the weight."

Choose Your Proteins Wisely

The type of protein you eat may play a role in successful weight loss and in your overall health.

Consumption of large quantities of processed meats such as hot dogs, sausages, and deli meats, have been linked to increased risk of type 2 diabetes, cardiovascular disease, and colorectal cancer, Hu says. You'll have a harder time maintaining weight loss if you eat these proteins often, and you may be damaging your body.

Hu and other nutrition experts recommend getting dietary proteins from the following sources:

• Fish: Fish offers heart-healthy omega-3 fatty acids and, in general, less fat than meat.
• Poultry: You can eliminate most of the saturated fat by removing the skin.
• Beans: Beans contain more protein than any other vegetable protein. Plus, they're loaded with fiber that helps you feel full for hours.
• Nuts: One ounce of almonds gives you 6 grams of protein, nearly as much protein as one ounce of broiled ribeye steak.
• Whole grains: A slice of whole wheat bread gives you 3 grams of protein, plus valuable fiber.

"A lot of plant-based foods like soy and legumes can give you the same amount of protein as meats. I have nuts for breakfast every day, because they not only give you a lot of protein, but they're healthy sources of fat," Hu says.

So when you decide to cut carbs and boost protein, take Hu's advice: Don't lose sight of the big picture.

Published March 31, 2004.

SOURCES: Frank Hu, MD, PhD, assistant professor, Department of Nutrition at Harvard School of Public Health, Boston; Christopher D. Gardner, PhD, Assistant Professor of Medicine (Research), Stanford University, Palo Alto, CA; Deborah Sellmeyer, MD, assistant professor of medicine and director of the Center for Osteoporosis, UCSF; Nelson, Miriam. "Will Eating More Protein Help Your Body Gain Muscle Faster?" WebMD Medical News Archives; American Heart Association. Nutrition and Your Health: Dietary Guidelines for Americans (5th ed., 2000), available at http://www.health.gov/dietaryguidelines.

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