1. Warn someone in charge of cooking and planning events that you have certain goals tactfully and in advance.
I informed my step mom a week before going home that I am getting ready for a contest. It's better to make the person preparing food aware ahead of time rather than refusing to eat anything upon arrival. Offer to prepare all of your own food or help with food prep to make yourself useful and ensure that your food is acceptable.
2. Just toss the cookies at home NOW!
This applies to pies and holiday candies too; they're not fresh now and you will consume them if they are easily accessible. Step away from the dessert table! Play with you niece; show off the three chords you can strum. Crappy food is totally not the point of the season!
3. Always have lean protein and cut veggies ready to eat now! Bring the token veggie platter to parties and stick to that.
Healthy alternatives need to be available to choose the healthy food! Be proactive and ensure that you have what you need on hand!
If you really need something sweet, bring a few pieces of hard candy and have one if the urge strikes. They are only 20 Calories and will last far longer than a cookie!
4. Think of yourself as a role model for relatives that want to live healthier.
If people can see you following a plan, it may give them more motivation. Tune out naysayers and stick to your goals!
If you have a relative who has been seriously interested in exercising, get bundled up and go for a walk or a sledding adventure. Show your loved one that fitness is a lifestyle that should begin before the New Year and continue indefinately!
5. Change your gym schedule so that it works during this time period.
Right now I am with my family in NY. Usually I work out in the very late afternoon or early evening; it's the time that usually fits well into my schedule and I feel pretty strong at that time. However, in NY, my parents get out of work at in the evening, and I am not going to ditch them every night to maintain my normal gym schedule. As such, I've shifted to morning workouts, even though I hate it. Compromise a little so that you can keep a regular schedule without conflict or guilt.
Give yourself the time to treat your body well--it will thank you!