According to Weight Watchers, most of us eat more on Thanksgiving than on any other holiday. We rationalize that it's just one day a year, so what's an extra 2,000 calories? And it's tradition, after all. Maybe it's time for a new tradition. "I try to encourage people not to gain weight over the holidays," says Judy Fields, a registered dietitian in Fair Oaks, Calif., who specializes in weight control. That doesn't mean you should beat yourself over the head if you do gain a little weight during party season. "A normal fluctuation is 3 pounds for women and 5 for men. If you don't allow yourself to go over that, it will be much easier to deal with in January," Fields says.