Heart Benefits Found in Low Carbs, Some Fats
Thursday, November 9, 2006
Women who eat a diet moderately low in carbohydrates, but rich in vegetable fat and vegetable protein, can cut their risk of heart disease by as much as 30 percent compared with just following a low-fat approach, according to a new Harvard study.
The findings, drawn from a study of more than 80,000 nurses, reinforce a growing shift in nutritional advice toward moderate amounts of healthful fat found in such foods as nuts, avocados, liquid vegetable oils and seafood along with less-processed carbohydrates, including whole-grain bread and cereal and fruits 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 35 percent of daily calories as fat, most of it from healthful sources, and boosting consumption of beans and legumes, fruit and vegetables as well as healthful, 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 healthful vegetable oils "can help reduce the risk of heart disease," said Alice H. Lichtenstein, a professor at Tufts University's Friedman School of Nutrition Science and Policy.
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 approach to carbohydrates that some experts say is more akin to the South Beach Diet.
"We didn't really design the study to look at weight loss," said lead author Frank Hu, associate professor of nutrition and epidemiology at the Harvard School of Public Health. But after analyzing 20 years of food information collected from participants who reported eating a moderately reduced carbohydrate diet, Hu and his colleagues concluded that there is "no significant long-term effect on body weight."
The findings suggest that "there's no magic formula for weight loss," said Lichtenstein of Tufts. "You still have to focus on calories."
The new study may also help to put to rest some concerns about heart disease that once dogged the reduced carbohydrate diets. But some experts including physician Dean Ornish, a proponent of a very low-fat, vegetarian approach that has been proved to reverse blocked arteries, cautioned that the report should not be used to resurrect the Atkins diet.
"I worry this will confuse people and potentially mislead them to think that low-fat diets don't decrease your risk of heart disease, because they do," Ornish said.
Gary Foster, director of the Center for Obesity Research and Education at Temple University and author of a study of the Atkins diet, said, "If I had one message to tell people, it would be to eat a little bit less of everything, and that everything does mean olive oil, too."