Yearlong study gives Atkins diet top marks

The largest and longest-running comparison of diet plans found the low-carbohydrate Atkins regimen produced greater weight loss than three other popular programs – the Zone, the Ornish and the U.S. nutritional guidelines.

The average weight reduction was small, and participants started regaining pounds by the end of the one-year study, according to the report in today’s Journal of the American Medical Association.

Still, Atkins dieters – who consume prodigious amounts of long-demonized saturated fats but shun carbs such as pasta and breads – experienced significant drops in blood pressure and cholesterol. The finding showed that even a small weight reduction can improve overall health, researchers said.

Atkins dieters lost an average of 10.4 pounds after one year, according to the report, compared with 5.7 pounds for those on a traditional balanced diet based on federal nutrition guidelines, 4.8 pounds for the high-carbohydrate Ornish diet and 3.5 pounds for the Zone diet, which calls for a set ratio of carbohydrate, protein and fat.

The study’s results cast further doubt on the benefits of low-fat, high-carb diets, which have been touted for decades as the model of healthy eating.

“This study confirms the importance of reducing carbohydrates,” said Dr. Frank Hu, associate professor of nutrition and epidemiology at the Harvard School of Public Health, who was not involved in the research. “Bagels, white bread, potatoes and soft drinks are the real bad guys in our diet.”

The study was quickly criticized by some Atkins competitors.

Dr. Dean Ornish, president of the Preventive Medicine Research Institute in Sausalito, Calif., said the differences among the weight loss plans detected in the study were insignificant.

He added that Atkins dieters saw an increase in levels of LDL, or “bad,” cholesterol.

“The conclusions of this study are highly misleading,” he said.

But Atkins backers saw the study as a vindication of their approach and predicted a revival of interest in the Atkins diet, which peaked in popularity five years ago but swiftly faded.

Atkins Nutritionals Inc., which sold packaged foods based on the diet, sought bankruptcy protection in 2005. Today, the $2-billion carb-conscious food market is dwarfed by the $14.7 billion spent on low-fat products, according to AC Nielsen.

“Those of us who have been in the low-carb community for decades are not surprised by these (study) results,” said Jacqueline Eberstein, coauthor of “Atkins Diabetes Revolution” with Dr. Robert C. Atkins, who died in 2003.

Marion Nestle, professor of nutrition, food studies and public health at New York University, said the study should be interpreted cautiously.

Women on the Atkins diet experienced most of their weight loss during the first six months, raising the possibility that weight loss on all four diet plans would look the same in a longer study, she said.

“My guess is that if they carried this study out for another six months, they would converge,” Nestle said.

The $2-million diet face-off, funded by the National Institutes of Health and the Community Foundation of Southeast Michigan, was conceived several years ago to sort out the cacophony of claims made by competing diet plans.

More than 300 overweight, pre-menopausal women were randomly assigned to follow one of the four diet plans, which were chosen to represent the range of low- to high-carbohydrate diets. The Zone and the traditional diet, called LEARN, included calorie-restriction goals but the Atkins and Ornish diets did not.

When the study began, the women weighed an average of 190 pounds and had an average body mass index of more than 30, putting them into the obese range.