Low-carbohydrate diets are better for losing weight and protecting the heart than low-fat diets, according to a new Tulane University study published in the Annals of Internal Medicine.
[Photo: Dr. Lydia Bazzano]
The study followed 148 obese participants who were randomly assigned to either a low-carb diet, consuming less than 40 grams of digestible carbs per day, or a low-fat diet, consuming less than 30 percent of daily calories from fat. Researchers gave both groups dietary advice, but neither had strict calorie or exercise goals.
After a year, the low-carb group lost an average of 7.7 pounds more than the low-fat group. The blood levels of certain fats that are predictors of heart disease risk also improved more in the low-carb group. While low-density lipoprotein cholesterol for both groups were about the same, the low-carb group saw a spike in so-called “good” HDL cholesterol and a decline in the ratio of bad to good cholesterol.
The results challenge the perception that low-fat diets are always better for the heart, said lead author Dr. Lydia Bazzano, Lynda B. and H. Leighton Steward Professor in nutrition research at Tulane University School of Public Health and Tropical Medicine.
“Over the years, the message has always been to go low-fat,” Dr. Bazzano said. “Yet we found those on a low-carb diet had significantly greater decreases in estimated 10-year risk for heart disease after six and 12 months than the low-fat group.”
The results do not mean it is okay to binge on butter. While the low-carb dieters got 41 percent of their calories from fat, most were healthy monounsaturated and polyunsaturated fats like olive or canola oil. The group only got 13 percent of calories from saturated fats like butter.
“It’s not a license to go back to the butter, but it does show that even high-fat diets – if they are high in the right fats – can be healthy and help you lose weight,” Dr. Bazzano says.