There is a very common tendency to set all good eating habits aside during "the Holidays," possibly starting as early as Halloween. I have been no stranger to such wild abandon, and let's just say, the results were unsatisfying.
What I routinely remind myself this time of the year is that Thanksgiving Day is a holiday and Christmas Day is a holiday, but all the other days between and around them are NOT holidays. This is a strong motivator to eat in my usual healthy manner on those non-holidays, so that when I do indulge on a holiday, it's not months of recovery to get back to normal.
Also, I have a few (2-3) Christmas-party type of events this year. At those I allow myself to eat whatever I want, with the goal of simply not making myself uncomfortable with quantities. That way I don't feel deprived through the season, which is a real danger mode for me.
We take care of what we value, and I value my great health. Today is not a holiday, and I will eat well. And as a result, I will enjoy Christmas Day more than ever.
Happy non-holiday to you!