The holidays are a great time to take time off and enjoy good food, wine, and family. There are going to be days where living it up is the far better choice than eating in moderation. And on those days, go for it! Being in the moment with family and friends is more than worth it.
Don't worry, I have done the math for you:
Lets assume that your current basal metabolic rate (the number of calories you burn if you laid in bed without moving for 24 hours) is 2,000 calories per day. If you ate 2,000 calories per day, you would eat 730,000 calories in one year. Let's say you were aggressively trying to lose weight instead and set your weight loss goal to consume 1,500 calories a day. During a one year period, you would eat 547,500 calories. The deficit would be approximating 25% resulting in weight loss from one to two pounds a week depending on how much you weigh. Now lets say that you wisely decided to take off 10% of there year where you planned to eat and drink in excess and on those days you consumed 5,000 calories. So approximately 36 days of the year you consume 5,000 calories and the rest of the time you eat 1,500 calories. Your total calories consumed would be 673,500 or an 8% deficit. So you wouldn't lose as much weight in a year but you would lose weight and have a lot more fun. Now most people don't take that many days off and when they do, at least speaking from personal experience, they rarely eat that many calories. Often times, when I have made a habit of eating the right number of calories, my cheat days would end up being 2,500 to 3,000 calories. Which usually means I had a couple of craft beers (345 calories per glass), a couple extra glasses of wine (185 per glass), pizza, or dessert. Which was plenty for me to feel like I was not only cruising through the weight loss but having fun while doing it. The point is, when it is time to celebrate and have fun, do it, and don't even think twice about diet frameworks or losing weight. If you eat right most of the time you will lose weight. So enjoy the times when you don't!