Summarize this article:

If you choose to eat pasta salad, then you should skip dessert.  Alcohol lets down your inhibitions, and your body burns it before it burns fat and carbs. Alternatively, take 1 bite and tell the host that the dessert is delicious but that you are too stuffed to eat more.

Summary:
Eat a substantial snack or even a meal before an event to temper your appetite. Make only 1 trip to a buffet table. Pick your poison. Eat until you are satisfied but not stuffed. Drink alcohol only in moderation. Say that you're too full for dessert.