FMT- You may want to volunteer to help with some of the cooking/meal planning? I'm vegetarian and I've found this is the solution to making sure I have something I know I can eat.
And like Lisa said, budget in for some of the meals. You will probably have to give in and eat things you wouldn't normally, but portion size is often the main culprit to gaining versus the food (unless you're talking about fried chicken and biscuits with gravy! )
Also, getting up a bit earlier to go for a run around the area (which I always love running in new locations!) or a walk after dinner or something will help some. With a walk, you could even get others involved. Go look at the Christmas/New Year's decorations? Play with the nieces/nephews at the park? You see where I'm going with this!