and this one:
In 2008 Stampfer co-authored a study in the New England Journal of Medicine that followed 322 moderately obese individuals for two years as they adopted one of three diets: a low-fat, calorie-restricted diet based on American Heart Association guidelines; a Mediterranean, restricted-calorie diet rich in vegetables and low in red meat; and a low-carbohydrate, nonrestricted-calorie diet. Although the subjects on the low-carb diet ate the most saturated fat, they ended up with the healthiest ratio of HDL to LDL cholesterol and lost twice as much weight as their low-fat-eating counterparts.
Will the more recent thinking on fats and carbs be reflected in the 2010 federal Dietary Guidelines for Americans, updated once every five years? It depends on the strength of the evidence, explains Robert C. Post, deputy director of the U.S. Department of Agriculture’s Center for Nutrition Policy and Promotion. Findings that “have less support are put on the list of things to do with regard to more research.” Right now, Post explains, the agency’s main message to Americans is to limit overall calorie intake, irrespective of the source. “We’re finding that messages to consumers need to be short and simple and to the point,” he says. Another issue facing regulatory agencies, notes Harvard’s Stampfer, is that “the sugared beverage industry is lobbying very hard and trying to cast doubt on all these studies.”
“If you reduce saturated fat and replace it with high glycemic-index carbohydrates, you may not only not get benefits—you might actually produce harm,” Ludwig argues. The next time you eat a piece of buttered toast, he says, consider that “butter is actually the more healthful component.”