Being a gracious guest doesn't mean eating hearty portions of everything that's offered. "Don't feel the need to eat foods you'd normally avoid, or take seconds, just to please the hostess," says Jill Fleming, author of Thin People Don't Clean Their Plates. "Regardless of the occasion, you need to be the one who is in control of what and how much you eat."

If you find refusing food awkward - or have a relentless relative who's always begging you to "Eat! Eat!" - try the broken-record technique: Continue to simply say "No, thank you," with a smile. It's impossible for your hostess to argue with a gracious but firm "No," and if you don't make complicated excuses, you're less likely to cave in to pressure.

2. Don't Fast Before Big Events

"To prepare your body for the big feast later in the day, you may be tempted to 'save' calories by skipping breakfast or other meals," says Fleming. "While eating every few hours is always important, it's essential before a holiday gathering." Why? It keeps your metabolism high, allowing your body to continue burning calories, instead of sending you into starvation mode, in which your body hangs on to them.

Eating something beforehand also prevents you from becoming so famished that you devour fatty foods at the event. In fact, it might be smart to eat more than you normally would that day. "Never go to a party starving," advises Fleming. "Even something small, like a banana or a bowl of cereal, will take the edge off your appetite and allow you to make smarter food choices." And if you're not sure whether healthy items will be available, offer to bring a platter of veggies and low-fat dip.

Next page: Moderating alcohol and more