Well it isn't really a question of whether or not to eat. It is Thanksgiving, after all... it would just be rude to leave that turkey all alone. The question is how much should you eat and will you get fat, etc. Do you even care? I for one don't, but I also can count macros and calories just by looking at most foods pretty well at this point. So I can compensate if I even care to.
There's a few ways to make this simple.
1. Eat as much as you want. Worry about the calories later. By doing this you get your feast on and satisfy your fat side. In doing this you basically just have to eat less the next day or two and do a couple hours of cardio over the next couple days. This approach isn't recommended if you're already overweight and trying to lose a lot of weight.
I also don't recommend this if you have a history of binge eating which will set you up for a bad binge eating pattern. You know who you are so just be smart about it!
2. Eat just enough to keep you satisfied. Try a little of everything instead of a lot of everything you want. After all you will live to eat another day. Take home some of the things you really like for later. By breaking the meals up you will most likely be able to eat less calories without feeling like you are going to burst. Eating while you're 'food blind' and hungry tends to be the worst way to overeat. Straight logic will get you everywhere and self control is a good thing almost always.
Fill your plate up eat half and save the other half for later. Let everyone know you will stab them with a fork if they invade your plate.
3. Eat less the day before. Have you ever noticed that when you eat less you can't really eat big meals easily anymore? Well the stomach adapts and expands according to your habits daily. If you eat less or fast the day before you surely won't be able to stuff down as much without flopping over at the table helplessly writhing from the extra stuffing you ingested.
I saw someone on Facebook say they were going to eat less today so they could eat more tomorrow. It doesn't really work that way. If that's the plan you're better off sticking to plan A.
4. Make your own desserts and sides. By knowing what's in the food you're eating you know how much fat and extra sugar may be in the dishes. The turkey should be fine since it's mostly just protein anyways. It's those sides and desserts that add up quickly.
5. Moderation and education. The best way to keep from getting too fat and going overboard is just being aware of everything you are eating. I know this is kind of just a combo of the first 4, but it's just the simple truth. The more you know the more you grow...not in the belly. Once you understand how the body partitions food and nutrients you can make adjustments on the fly. On top of all that, just exercise regularly and you won't have to worry about all these silly holiday lbs we complain about every single year.
Stick to high protien foods for the majority of your intake, high fat is fine as long as it's not too high. Stick to 100 grams or less for the day if you can. Go easy on the carbs unless you plan on doing some marathon runs over the next week.
It's pretty simple stuff. We just tend to over-complicate things for the most part. Eat less, move more = lose weight. Eat more, move less = gain weight. There are details that make a difference, but if you are doing these things consistently then it's pretty standard for the average person.
I hope you all make something delicious and share it with the family and the ones you love. Appreciate the time with these crazy people because without them you would not be possible. Tell these people you love them even if they get on your nerves mostly. Have a great holiday everyone!