Honestly that IS the struggle of the holidays isn't it?
There are many factors at play when it comes to breaking bad habits, especially food related habits, and being aware is the first step to get you on the path towards change. If this sounds like the beginning of a rehab program, well, it kind of is.
You see there are 5 factors that affect your ability to break a food eating habit:
Your brain makes associations between things that were present and brought comfort with things that cause bad feelings.
EXAMPLE: My brother-in-law was an only child and when his parents needed him distracted so they could get some work done (if you're a parent you can feel the need, right?) they would sit him in front of the television with a Snickers bar. Two things came from this, first he gained weight rapidly as a child and struggled with obesity since it was effective his parents employed it often. The other issue that arose from this is that he would continue this practice on his own as he became an adult as a stress coping mechanism.
ACTUALLY there are three issues that arose from this with the third being it created an unhealthy relationship with food (food = soothing comfort, mindless consumption).
Here is a great video presentation here that outlines all 5 factors involved in breaking a habit:
HOW TO QUIT SUGAR & UNHEALTHY HABITS.