I'm not a fan of ultra strict dietary practices during the holidays. Not to say you should throw all caution to the wind, but the way I see it, holidays come around one time a year so you should enjoy it, indulge a little bit ;) Having a good time with family is much more beneficial to your overall health and wellbeing than stressing over what you can and can't eat.
The exception: if you have a medical condition or personal belief that requires you to have a specific diet/way of eating then definitely stick to it. Enjoy by contributing or making dishes you can eat with everyone.
Some things to consider with indulgence:
Consider quality and freshness of ingredients. I normally eat a paleo or grain-free diet because I feel better that way but when I was in Paris, I ate bread and butter everyday ..and felt amazing! I wondered why this was and my only conclusion is the fresh, unprocessed ingredients mixed with enjoying every moment made a huge difference. (BTW --I'm not at all suggesting this diet ;)
Balance. The key is to balance the indulgence and deprivation. Find that sweet spot where you're enjoying without overdoing it. Which brings me to my next point...
Know your limits! Just because it's there and you can have it doesn't mean do it till you overdo it. The body is always giving us clues, listen for those clues and use them as a guide of how much you can afford to indulge (or not indulge).