Not all calories are the same when it comes to keeping weight off.
Researchers from Children's Hospital Boston say participants in a recent study lost 10 to 15 percent of their body weight over 12 weeks.
It involved eating pre-prepared meals containing 60 percent of their usual calorie intake.
Then, the researchers compared three diets to see which worked best.
They compared low fat, low carb, and the Atkins diet.
Their research concluded that, if you really want to lose weight and keep it off, you need to eat less.
You should also avoid high-glycemic index foods-such as refined sugars and processed foods.
These could slow down your metabolism and cause you to gain weight again.