If you're dieting, you know you've got to count calories, carbs and fats. But if you really want to take off the weight and keep it off, you might want to pay more attention to the glycemic index, which is essentially a measure of how quickly foods are digested.
That's because high glycemic foods cause a surge in blood sugar, followed by a crash. That biological reaction releases hormones that stimulate hunger and, according to David Ludwig of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital, actually lower metabolism, adding up to a dismal recipe for people who want to lose weight and keep it off.
"One of the unfortunate aspects of weight loss maintenance is that it takes fewer and fewer calories to just stay the same," Ludwig says. "As the body loses weight, it becomes more efficient and requires fewer calories," making it harder and harder to continue losing and making it difficult to maintain weight loss without continually dieting. By some estimates, only 1 in 6 Americans who lose weight are able to keep it off after one year.