Once you've successfully lost some weight, all you have to do is count calories to keep it off, right? Wrong, according to an admittedly small but intensive study that basically determined that all calories are not created equal. Twenty-one overweight/obese participants followed a 12-week weight-loss program designed to peel off 10% to 15% of their body weight, followed by a four-week weight-stabilization program. Then came the test: The subjects tried three diets for four weeks each: low-fat, low glycemic index, and low-carb. Those on the low-carb diet, which was also high in protein, burned more than 300 additional calories compared to those on the low-fat diet.
"That's roughly equal to an hour of moderate physical activity—without lifting a finger," the study author says. The Los Angeles Times shares the breakdown: The low-carb diet was made up of 10% carbs, 60% fat, and 30% protein, compared to 60% carbs, 20% fat, and 20% protein for the low-fat diet. Interestingly, the head researcher doesn't recommend the low-carb diet though, since it can be hard on the heart; fortunately, the low glycemic index diet (40% carbs, 40% fat, 20% protein) was also successful: Subjects on that diet, which centers around whole grains, fruits, and vegetables, burned 200 more calories than those on the low-fat diet.