Calorie is not always just a calorie, says study

A small US study finds that some calories may count more than others, and that certain foods and diets may be better than others for helping people maintain weight loss.

A small US study finds that some calories may count more than others, and that certain foods and diets may be better than others for helping people maintain weight loss.

In the research, 21 obese participants who had lost weight agreed to follow a low-fat, very-low-carb, or a low-glycemic-index diet for a month. While each group ate the same number of calories on each of the three plans (about 1,600 a day), subjects burned about 300 fewer calories a day on the low-fat eating plan than they did on the very-low-carbohydrate one, which was modeled after the Atkins diet.

"That's the amount you'd burn off in an hour of moderate intensity physical activity without lifting a finger," says senior author David Ludwig, director of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital.

"Participants burned 150 calories more on the low-glycemic index diet than the low-fat diet. That's about an hour of light physical activity," he adds.

"We think the low-carb and low-glycemic index diets, by not causing the surge and crash in blood sugar, don't trigger the starvation response," he adds. "When the body thinks it's starving, it turns down metabolism to conserve energy."

The study was published online on June 27 in the Journal of the American Medical Association.

While experts suggest more research needs to be done before clinical recommendations can be given, another study gives good reason to mind the carbs. Published in the journal Archives of Internal Medicine, findings show that women who overload on simple carbohydrates are more likely to develop heart disease.