The holidays are such a tough time of year. There are all of the parties, so food is plentiful, and time is at a premium. Here's what I usually observe during the holidays, as a trainer.
*One cookie won't hurt (make that two, no three!)
Well, one won't if properly budgeted for, but a plateful will not help you!
*I won't eat all day, then I can eat whatever I want at this party.
No. Your metabolism will bottom out, then you will eat and your body will conserve that food well and store any extra as fat. This is a great way to put on weight.
*Missing one workout won't matter.
Yes, this one matters just like all the rest. If you don't burn regularly, especially during this time of year, you will put on fat. Your body is programmed to do so. And, this usually turns into a whole bunch of missed workouts! Danger, Will Robinson!
*Also not on my list as a good idea: skipping the whole month to enjoy festivities. You will pay dearly for this one come January.
So, stick with your regular workout program, eat sensibly, don't starve, and don't overeat. My Mother always says "everything in moderation"!