Study: Low-carb diet beats low-fat for weight loss and heart health


Good news for people who like oil more than bread: People on a low-carbohydrate diet lowered certain risk factors for cardiovascular disease and lost nearly three times as much weight as those on a low-fat diet, a new study found.

“This isn’t a license to hit the butter and meat fats,” cautioned Dr. Lydia Bazzano, a professor at the Tulane University School of Public Health and Tropical Medicine and one of the study’s lead authors. “But even very high-fat diets can be healthy.”


FOR THE RECORD, 4:56 p.m.: An earlier version of this article said “bad” cholesterol was HDL and “good” cholesterol LDL. In fact, “bad” cholesterol is LDL and “good” is HDL.



The yearlong study, published this week in the Annals of Internal Medicine, found that total and “bad” (LDL) cholesterol levels — considered a primary risk factor for heart disease — went down equally for both groups, but “good cholesterol [HDL] went up quite a bit more on the low-carb diet than it did on the low-fat diet,” Bazzano said.

At the end of the study period, participants in the low-carb group had lost nearly 12 pounds on average. Those in the low-fat group had lost 4 pounds on average.

The people in the low-carb group were told to have less than 40 grams of digestible carbohydrate per day, and those in the low-fat group were told to get less than 30% of their daily calories from fat (less than 7% from saturated fat) and 55% from carbohydrate.

Neither group got a limit for total caloric intake, and participants were told to keep getting as much or as little physical activity as was normal for them.

All participants got counseling sessions that Bazzano said covered topics such as planning meals, portion size, what to do at restaurants and how to read nutrition labels. It’s unclear whether people who have similar diets but don’t get such counseling would have similar results, the study noted.

Bazzano said participants were also educated about different kinds of fats. Monounsaturated fats (such as canola and olive oils) and polyunsaturated fats (found in foods such as nuts and fish) were “recommended,” she said. Saturated fats — generally speaking, those that are solid at room temperature — were “not recommended.”

The study isn’t the last word on what kind of diet is best. An analysis published Tuesday in the Journal of the American Medical Assn. looking at 48 studies involving overweight or obese participants found significant weight loss with any low-carbohydrate or low-fat diet.

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