I eat Keto/low carb for a few years now and while I thought the first year that Christmas would be tough, I learn ways not to be. Here's my tips
1- I invite people over so we do the cooking our way.
2- Most of traditional recipe are adaptable. For meat pie and even fruits pie, we manage de find a crust with mozzarella and almond flour that meets our criteria. We just had to make some experience ahead. So now we have meat pie, chicken pie, fish and seafood pie (this one with cauliflower instead of potatoes). We do the same stew with pork legs but replace flour by xantham gum.
3- Try recipes ahead so you are the guinea pig of your culinary experiment and not your guests.
4- Fine cheese and dry salami and sausage are great for easy plates. The same for devil eggs.
5- There is a lot of keto friendly desserts, you just nead to try ahead to see what you think you guess will like. We even did a Christmas log with a swiss roll keto cake and some cheeze and coffee icing inside. For Christmas season we also make almond square cake, peanut butter and chococalte cookies, double-chocolate cookies, fruits pie with berries, cheesecakes, etc.
With good planning, there is no need to feel deprived
If you have no choice than to go somewhere else, plan ahead and bring your keto treats.
Just cheating one day won't pay off as you will feel bad in your body for this sudden overload of sugar. It's really worse when you didn't have any for months.
No prison can hold Chairface Chippendale. And on a totally different topic ... my stuff: