Some High-Fat Diets May Not Harm Heart
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Some High-Fat Diets May Not Harm Heart
Harvard Study Finds Eating
Fewer Carbs, Healthier Fats
Can Reduce Cardiac Risk
By DAVID ARMSTRONG
November 9, 2006; Page D1
Diets low in carbohydrates and higher in fat might not be bad for the heart -- at least when compared with low-fat, high-carbohydrate diets that are sometimes advocated by doctors, according to a new study published in this week's New England Journal of Medicine.
Because some widely followed low-carb diets, such as the once wildly popular Atkins diet, often encourage eating meat high in saturated fat, several medical groups have urged people to avoid them because of fears those regimens will lead to an increased risk of heart disease. Other well-known diets that stress low-carbohydrate consumption include the South Beach Diet and the Zone. The study didn't compare specific approaches.
Women who ate a low-carb diet and limited animal fat cut their risk of heart disease by 30%.
The study from researchers at the Harvard School of Public Health found a low-carb, high-fat diet didn't result in any added heart risk when compared with a diet high in carbohydrates but low in fat. Such low-fat diets are typically recommended by doctors concerned about heart risk.
The researchers, however, were quick to warn their study wasn't an endorsement of Atkins or like diets. Indeed, the study also showed the benefit of eating a diet low in both carbs and animal fat: women who ate a low-carb diet but avoided animal protein actually cut their risk of heart disease.
"We don't want anyone to eat bacon or sausage for breakfast every day," said lead author Thomas L. Halton, a nutritional consultant who recently left Harvard.
The results were based on analysis of food questionnaires filled out every two years for 20 years by more than 82,000 women as part of the Nurses' Health Study, a decades-long research project that tracks the health of tens of thousands of nurses to identify risk factors for major diseases. Each woman was given a score based on the percentage of calories generated by carbohydrates, fats and proteins. The results were adjusted for factors such as whether the woman smoked.
Frank Hu, another author who is a professor of nutrition at Harvard, said one reason for caution in interpreting the results is that neither of the two diets being compared is ideal. Some low-carb diets encourage consumption of animal fat that is linked to an increased risk of heart disease. But in the high-carb group, he said, fat is often replaced with less nutritious, refined carbohydrates such as white bread and potatoes.
"We are talking about two diets that are unhealthy in different ways," he said.
In fact, women who adopted unhealthy aspects of carbohydrate intake -- such as consuming refined
Sugar from sources like soda and eating highly processed foods -- nearly doubled their risk of heart disease. On the other hand, women in the low-carbohydrate group who eschewed steaks and other animal fats for vegetable fat sources -- such as avocados and olive oil -- reduced their risk of heart disease by 30%.
The study is unlikely to persuade groups opposed to high-protein diets to change their views.
"I don't think nutritional guidelines will be influenced by this article," said Robert Eckel, a past president of the American Heart Association and a professor of medicine at the University of Colorado.
The heart association doesn't recommend high-protein diets for weight loss, because some of those diets restrict foods that provide important nutrients, while others don't provide an adequate variety of foods.
The Harvard study didn't specifically examine weight loss associated with the various diet approaches but did note that a low-carb diet didn't have a significant, long-term effect on weight.
Low-carb diets gained in popularity following the 1997 reissuance of Robert Atkins's 1970s-era diet book. Recently, however, the Atkins diet has waned in popularity. Last year, Atkins Nutritionals Inc., the company behind the low-carb diet craze, filed for bankruptcy. The low-carb approach has been hurt by criticism from nutritionists as well as studies showing that people have a hard time sticking to the diet and keeping off weight lost in the first few months of the program.
Write to David Armstrong at david.armstrong@wsj.com1
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