Diet Fare Matters Less Than Diet Devotion

TUESDAY, Jan. 4, 2005 (HealthDayNews) -- Pick a diet, any diet. Just vow to stick with it if you want to lose weight.

So says the author of the latest diet comparison study, which found no substantial differences in weight loss among dieters assigned to follow four popular plans.

Dr. Michael L. Dansinger, of Tufts-New England Medical Center, and his colleagues assigned 160 dieters -- aged 22 to 72, and all with cardiac risk factors such as high blood pressure and blood cholesterol levels -- to either the Atkins, Weight Watchers, Zone or the Ornish diets. They followed the dieters for up to a year to evaluate weight loss and reduction of heart disease risk factors.

Average weight loss at one year was 4.6 pounds for Atkins (which minimizes carbohydrate intake but does not restrict fat), 6.6 pounds for Weight Watchers (which emphasizes portion control and calories), 7.1 pounds for Zone (which suggests a caloric ratio of 40-30-30 for carbohydrates, proteins and fats) and 7.3 pounds for Ornish (which restricts fat).

Subjects on all the diets decreased their total cholesterol and other risk factors, with no substantial differences between the groups.

But the drop-out rate for each diet warrants special attention, said Dansinger. Twenty-one of the 40 Atkins dieters completed the study, as did 26 of the 40 people on Weight Watchers, 26 of 40 of the Zone dieters, and 20 of 40 on the Ornish plan.

"The more you follow the diet, the more you lose," Dansinger said.

Had subjects been allowed to choose their own diet, they might have stuck to them longer, he speculated.

The findings, which appear in the Jan. 5 issue of the Journal of the American Medical Association, suggest that doctors need to better tailor the diet to the patient.

"Doctors need to learn to use a broad spectrum of diet options to help match patients with the diets they can follow," Dansinger said. "Patients need to work in partnership with their doctor to try a variety of different eating strategies or diets."

In an accompanying editorial, Dr. Robert Eckel, an endocrinologist at the University of Colorado Health Sciences Center, said dieters should heed the recently released joint lifestyle recommendations of the American Heart Association, the American Cancer Society and the American Diabetes Association. These guidelines endorse an eating plan high in fruits, vegetables, whole grains and fish to reduce the risk of diabetes, cancer, heart disease and stroke.

"Weight Watchers most closely resembles the diet [recommended by the three]," said Eckel, president-elect of the American Heart Association.

Another study concludes that if you're looking for proof of a diet plan's effectiveness, don't expect to find much research to guide you.

Thomas A. Wadden reviewed diet plan Web sites, searched for published medical journal reports, and interviewed representatives of popular diet regimens, trying to report on the effectiveness of each.

Weight Watchers had the strongest studies to support effectiveness, said study co-author Wadden, a professor of psychology and director of the Weight and Eating Disorders Program at the University of Pennsylvania School of Medicine.

"Weight Watchers is the best studied program," Wadden said. "There were three randomized trials." The largest reported a loss of 3.2 percent of initial weight at two years, he said.

"Just because there is no data [for other programs] doesn't mean they won't work," Wadden said. The studies without published data, including Jenny Craig, LA Weight Loss, Overeaters Anonymous and Take Off Pounds Sensibly (TOPS), may also work, he said.

"Pick a program that fits your needs," Wadden suggested. Ask if the counseling is group or individual, if the food is prepackaged or you make your own. "Try to figure out what you think is going to be helpful," he said.

Wadden's study appears in the Jan. 4 issue of the Annals of Internal Medicine.

More information

To learn more about selecting a weight-loss program, visit the American Heart Association.