By Maureen Williams, ND

Healthnotes Newswire (February 21, 2008)—Weight-loss diets that push protein and restrict carbohydrates have become increasingly popular in the past decade, but do they work? A new study says they can. Researchers found that women on a high-protein diet kept more weight off at the end of a year than women on a high-carbohydrate diet.

In the never-ending quest for weight loss, ideas about the best way to diet come and go. Low-fat diets that emphasize carbohydrates (typically starches and grains) were the standard not long ago, but more recently there has been a shift to low-carb diets that emphasize protein. A number of studies have found that carbohydrate restriction can lead to more rapid weight loss than low-fat diets, but findings from other studies suggest that this difference evens out after one to two years.

The new study, published in the American Journal of Clinical Nutrition, followed 79 overweight women between the ages of 40 and 58 for one year after finishing a 12-week weight-loss program. The program involved either a calorie-restricted, high-protein diet, with 34% of calories from protein, 46% from carbohydrate, and 20% from fat, or a calorie-restricted, high-carb diet, with 64% of calories from carbohydrate, 17% from protein, and 20% from fat. After the intensive program, the women kept track of their eating and were monitored every three months.

Women on both diets had trouble sticking to their eating plans. Calories increased in both diet groups and protein intake dropped off in the high-protein group. But for women who managed to keep their protein portion up, the reward was more sustained weight loss at the end of the year: about 14 pounds (6.5 kg), compared with about 8 pounds (3.6 kg) for those eating the high-carb diet.

“A lot of women are drawn to these high-protein, low-carbohydrate diets because they see results quickly,” commented Elaine Shamos, director of the Women’s Health Resource Center of Dartmouth Hitchcock Medical Center. “I’m not surprised that the women in the study had a hard time staying faithful to the diet—it’s very hard to avoid the refined carbohydrate foods because they are constantly available…. In our society, people need a lot of support in developing healthy eating habits.”

It is interesting to note that markers of heart health improved in women on both diets, including total cholesterol, LDL and HDL cholesterol, glucose, insulin, C-reactive protein, and homocysteine levels. These changes were associated with weight loss, but not with the protein content of their diet, suggesting that the road to weight loss might not be as important as the weight loss itself for keeping the heart healthy.

(Am J Clin Nutr 2008;87:23–9)

Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.

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