Study: Cut carbs, not calories, to lose weight

In a study of overweight people maintaining weight loss, those on a low-carbohydrate diet burned about 250 more calories per day than those on a high-carbohydrate diet.

The study of 164 people, published recently by The BMJ medical journal, notes the challenge of maintaining weight loss in the face of the resulting hunger and metabolism slowdown, and says that the calorie-burning effect of a low-carb diet “may improve the success of obesity treatment.”

“These findings show that all calories are not alike to the body, and that restricting carbohydrates may be a better strategy for long-term weight loss than restricting calories,” said study co-author Dr. David Ludwig, codirector of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital.

The study addresses one of the most vexing problems in weight loss: As the weight comes off, the body fights back, burning fewer calories and bombarding us with hunger signals.

Here’s the mystery: Why does the body react as if it’s starving when it clearly is not? For some researchers, the answer lies in the carbohydrate-insulin model, the theory that processed carbohydrates such as white bread trigger hormonal changes that lead to hunger, metabolic slowdown and weight gain.

Processed carbohydrates digest quickly into sugar, raising insulin levels, Ludwig said. Insulin, in turn, programs fat cells to store excess calories. When calories are locked up in fat cells, the brain can’t perceive them and thinks the body needs more food.