The Scoop on Carbs and Fats
A new study tries to make sense of diet and the risk of heart disease
The Harvard group found that women who ate higher glycemic index foods were twice as likely to have heart disease. This reprises research published in 2000 that found that overweight women with a high glycemic load diet were twice as likely to develop heart disease as were overweight women who favored low glycemic load foods. "You can eat a low-fat diet as long as most of your carbohydrates come from whole grains,"Hu says. "Unfortunately, the low-fat diets practiced by most people are not like that-there are a lot of refined carbohydrates and sugar beverages." Indeed, Hu speculates that one reason his research didn't find more heart disease among the high-fat eaters is that they were eating fewer refined carbohydrates.
Robert Eckel, immediate past president of the American Heart Association, says that the jury is still out on the glycemic load's effect on weight loss and heart disease. A study earlier this year based on data from the federal Women's Health Initiative, which tracked nearly 50,000 women over about eight years, found no increased risk of heart disease or diabetes from eating grains, starches, and sugars. Glycemic load, which is calculated by multiplying a food's glycemic index by the amount consumed, is a tricky measure, Eckel says. That's not only because it changes when foods are eaten together (eating a high-index bagel with low-index chili slows the bagel's conversion to glucose) and depending on how foods are cooked (al dente pasta has a lower glycemic index than overcooked pasta) but also because it's not a proxy for carbohydrate intake. "To come away from this saying that higher glycemic load causes more heart disease is unacceptable."
Although the Harvard study is "interesting and may be important," Eckel says people should stick with the federal government's 2005 recommendations for healthful eating: Keep fat intake at 20 to 35 percent of calories a day in the average 2,000-calorie diet, with most fats coming from fish, nuts, and vegetable oils. Saturated fats should account for less than 10 percent of calories daily, equivalent to about 200 calories, or two pats of butter. Trans fats are out altogether, and avoid refined sugar and caloric sweeteners in food and drinks. The U.S. Department of Agriculture also recommends eating three or more whole-grain foods a day, as well as 2 cups of fruit and 2
The bottom line, Hu says, is that there is no single optimal diet for everyone. "You can have a healthy low-carb diet or a healthy Mediterranean diet [with complex carbohydrates, vegetable oil, and fish]."But the emphasis is on the healthy. l