Distract the cook with compliments. “I couldn’t eat another bite because I’m so full from these amazing sweet potatoes! Can I have the recipe?”
Ask for hearty helpings. But only of the healthy, low-cal stuff such as greens, sweet potatoes, lean meat, etc., so there’s little room on your plate for much else.
Serve the pie. You know you won’t get out the door without a taste of the holiday desserts, so cut a slice yourself.
Get it to go. You can always ask if you can take the rest home…whether you actually end up eating it yourself or not.