1. Snack before you go out
Keep the scale on your side by arriving at holiday gatherings satiated, not starving. Before you leave home, eat a healthy mini-meal that has a balance of protein, fat, and carbs, such as a piece of toast with tuna fish, or apple slices with almond butter.
2. Bring your own dish
There's no better way to control what you eat than to make it yourself. "Bringing a dish to share is a great way to ensure you have something satisfying to eat that meets your dietary needs," says Summer Waters, a nutritional therapy practitioner based in Medford, Oregon. "Focus on foods that are mostly proteins, quality fats, and vegetables to provide nourishment without the empty calories from sugary, starchy foods." As an example, she suggests mushroom caps stuffed with your choice of ground meat and vegetables or vegetable-based proteins like tempeh.
3. Offer to serve
The amount of food on your plate influences how much you eat. An intriguing study gave adult participants free bowls of soup, except half the subjects' bowls were rigged to refill themselves. (It was subtle enough to be undetectable.) Amazingly, people who got the bottomless bowls of soup ate 73% more--yet didn't believe they had. Since portion size matters, offer to serve all the dishes (or at least yourself)!
4. Stick to a small variety
You've probably heard it's healthy to eat a wide variety of foods, but too much variety at one meal can actually contribute to weight gain. That's because our brains are programmed to like variety, and tasting a new food overrides the feeling of fullness. Limit yourself to bigger portions of three different foods at the buffet table and you'll probably eat less than if you allowed yourself to have, say, six smaller portions.
5. Drink in moderation
Alcohol converts straight to fat in the body, and because alcoholic drinks typically don't have any fiber or protein or fat--the three things that cause us to feel full--it's easy to drink a lot of calories. Even worse, alcohol relaxes your will power. The more you drink, the less likely you'll be to stick to your diet plan. Limit yourself to one drink per event, or better yet, sip on carbonated water.
6. Beef up your exercise routine
Nobody's perfect, and even the best of plans sometimes go awry. So if you do over-indulge this holiday season, kick up your cardio. Walk an extra 30 minutes or spend and an extra 15 minutes on the elliptical trainer and you'll burn almost 200 calories*--enough to justify two small holiday cookies.
*Based on a 150-pound person