The findings, drawn from a study of more than 80,000 nurses, reinforce a growing shift in nutritional advice toward moderate amounts of healthy fat found in such foods as nuts, avocados, liquid vegetable oils and seafood along with less processed carbohydrates, including whole grain bread and cereal, to fruit and vegetables.

Among the groups that have recommended that approach in recent years are the writers of the 2000 and 2005 U.S. Dietary Guidelines, the American Heart Association and the federal government's National Cholesterol Education Program. All advise eating 25 percent to up to 35 percent of daily calories as fat, most of it from healthy sources, and boosting consumption of beans and legumes, fruit and vegetables as well as healthy, whole grains.

The new findings, published in today's issue of the New England Journal of Medicine, underscore that eating few processed carbohydrates, such as bagels, white bread, cookies, candy and cake, and replacing animal fat with a moderate amount of healthy vegetable oils "can help reduce the risk of heart disease," said Alice Lichtenstein, professor at Tufts University Friedman School of Nutrition.

But such diets do not appear to have much effect on body weight -- a hope of many who once jumped on the widely popular very low-carbohydrate bandwagon advocated by the late physician Robert Atkins.

The latest findings examine a more moderate carbohydrate approach that some experts say is more akin to the South Beach Diet.

"We didn't really design the study to look at weight loss," noted lead author Frank Hu, associate professor of nutrition and epidemiology at the Harvard School of Public Health.

The findings suggest that "there's no magic formula for weight loss," noted Lichtenstein of Tufts. "You still have to focus on calories."