Study: Low-carb diet sheds more pounds than low-fat regimen

A long-running comparison of three diet plans found that the low-carbohydrate Atkins regimen and a Mediterranean diet rich in fish and nuts produced slightly greater weight loss than a low-fat program modeled on American Heart Association dietary guidelines.

The low-carb dieters - who consumed generous amounts of saturated fat but avoided such staples as bread and pasta - saw steeper increases in their HDL, or good, cholesterol, than people on either the Mediterranean or low-fat diets, according to a report in Wednesday's New England Journal of Medicine.

The study, funded in part by the Dr. Robert C. and Veronica Atkins Research Foundation, was the latest to demonstrate the benefits of diets high in fat, protein and cholesterol, which have long been demonized as unhealthful.

"It is time to reconsider the low-fat diet as the first choice for weight loss and for cardiovascular health," said study author Dr. Meir Stampher of Harvard Medical School. "It is not the best."

But Dr. Robert Eckel, a past president of the American Heart Association and a professor of medicine at the University of Colorado Health Science Center, said he was not ready to recommend an Atkins-type low-carb diet based on the results. People on a low-carb diet increased their consumption of saturated fat, he said, which could not be good for them in the long run.

LDL, or bad, cholesterol did not improve in any of the diet groups, said Eckel, who was not involved in the study.

The average weight loss in all three diet plans was small, and participants regained some of their pounds before the two-year study was over.

The study tracked 322 moderately obese people, all employees of a nuclear research facility in Israel, who were randomly assigned to one of the three diets.

The average age of participants was 52, and most were men.

The Mediterranean regimen - which included consumption of nuts, fish and olive oil - and the low-fat diet came with daily calorie restrictions. Men were limited to 1,800 calories and women to 1,500 calories. People on the low-carb diet had no calorie limit but were encouraged to choose vegetarian sources of fat, such as beans and nuts - more than is commonly associated with the Atkins diet.

Their intake of carbohydrates was limited to 120 grams daily compared with 400 grams in the typical U.S. diet.

To help participants stick to their programs, the workplace cafeteria prepared special meals for them, and nutritional counseling was available.

Spouses were trained to encourage participants, and participants tracked what they ate.

By the end of the study, subjects in all groups were consuming fewer calories and exercising more.

People on low-carb diets saw the greatest improvements in the HDL cholesterol and in a key ratio of total cholesterol to HDL cholesterol, which is used to assess cardiac risk. That ratio fell 20 percent in low-carb dieters, 16 percent in those on a Mediterranean diet and 11.5 percent in low-fat dieters.

Every 1 percent decline in the ratio represents a 2 percent drop in overall odds of developing cardiovascular disease, said lead author Iris Shai of Ben Gurion University of the Negev in Israel, which also funded the study.

"It is easy to identify the enemy - it is bread, potatoes, pasta and rice," she said.

For reasons not understood, women lost more weight on the Mediterranean diet while men did better on the low-carb diet, Shai said.
Although the study ended in June 2007, participants are being tracked to see how well they follow their diets under real-world conditions without special workplace meals and counseling, Shai said.

Dr. Kelly Brownell, director of the Yale Center for Eating and Weight Disorders and who was not involved in the report, said that the study should not be taken as a victory for low-carb diets because the people on the Mediterranean diet showed similar benefits. They also had an easier time maintaining their weight loss during the course of the study, he said.

Marion Nestle, professor of nutrition, food studies and public health at New York University, who was not involved in the study, said she was not that impressed with the benefits of any of the diets. The gains were meager and effort to achieve them great, she said.

The study has not changed her basic approach to weight loss: "Eat less, move more," she said.