Low-Carb Diet Most Effective, New Study Shows

By Maureen Williams, ND

Healthnotes Newswire (March 29, 2007)—Overweight and obese women have a wide array of popular weight-loss diets to choose from, but which is best? A new study compared four different diets and found the low-carbohydrate diet to be the most effective.

Despite the increasing awareness of the health consequences of overweight and obesity and a growing number of public health initiatives, Westerners keep gaining weight. Results from the National Health and Nutrition Examination Survey indicate that an estimated 66% of adults in the United States are overweight or obese.

Weight loss has become an enormous industry: Americans spend an estimated $30 billion annually on weight-loss products and programs. About 50 million Americans embark on weight-loss diets each year, but it is estimated that only 5% manage to achieve lasting results.

Pioneer Dr. Robert Atkins started promoting his program in the 1960s, advocating a diet that is very low in carbohydrates and high in fat and protein. In addition to promoting weight loss, proponents claim that the Atkins diet can stabilize blood sugar, even in people with diabetes.

Taking a radically different approach, Dr. Dean Ornish recommends eating a vegetarian diet rich in complex carbohydrates and very low in fat and cholesterol. Proponents of this diet point to its effectiveness in bringing down markers of heart disease as well as weight.

A more moderate approach, similar to the Ornish diet, has been advocated by conventional sources and was the basis for national guidelines set forth to promote better health through weight loss. This diet, known as the LEARN diet, is low in fat and high in carbohydrates, but is less restrictive than the Ornish diet.

Barry Sears’ “Zone” diet became popular in the 1990s and advocates carefully measured proportions of carbohydrate (40%), protein (30%), and fat (30%). This diet is lower in carbohydrates than a typical American diet, which is generally 40 to 75% carbohydrates, but is not as restrictive as the Atkins diet.

To compare the effects of these diets, 311 overweight or obese premenopausal women were recruited for the current study, which was published in the Journal of the American Medical Association. They were assigned to one of the four diet groups, were given the book to guide their diet, and were asked to attend eight weekly classes taught by a nutritionist. The exercise and nutritional supplement recommendations of each diet were also incorporated into the women’s regular lifestyles.

At the end of one year, women in the Atkins diet group lost the most weight—an average of 10.3 pounds (4.7 kg). The other groups experienced less weight loss: 5.7 pounds (2.6 kg) in the Ornish group, 4.8 pounds (2.2 kg) in the LEARN group, and 3.5 pounds (1.6 kg) in the Zone group. Only the difference between the Atkins and Zone groups was statistically significant. The Atkins diet also led to greater beneficial changes in blood pressure and markers of cardiac risk than the other diets.

“This study is important because so many people are looking for the best way to diet and lose weight,” commented Dr. Julianne Forbes, a naturopathic doctor in Maine. “It will be interesting to see if future research shows similar outcomes in a broader group of people—postmenopausal women, men, and people who already have diabetes or heart disease. In the meantime, the fact that very little weight was actually lost even on the ‘best’ diet should remind us of the importance of prevention. The findings from this and other studies tell us that dieters should expect real meaningful change to take a very long time.”

(JAMA 2007;297:969–77)

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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