Still others may be restrained eaters most of the time but have gained five to 20 pounds because they've let their guard down occasionally, falling prey to sweets and other high-fat treats. They have indulged themselves too much, too many times, or been lax about doing physical activity. The trick to being a happy restrained eater is to limit what you eat without completely depriving yourself. If you cut back so far on the foods you love that you no longer enjoy food, you'll end up feeling hungry, unsatisfied, unhappy, he says. One new study from Harvard Medical School shows that normal-weight girls who diet are more likely to become overweight than those who don't diet.
Experts say some people have to struggle more to control their weight than others.
And there is a small group of people who are going to be obese no matter what they do. But the vast majority fall somewhere in between. Whether they can maintain a healthy body weight depends, in large part, on how much effort they are willing to put into it. Genes and physiology play a role in how easy or difficult that is going to be, Hill says. Genes don't dictate weight but help set the upper and lower weight limits, experts say.