It’s not really a diet, but here’s how I eat on Thanksgiving or any other day I expect a huge afternoon/evening meal:
For breakfast I eat my usual high-fiber cereal with milk. I love it and prefer it to eggs or baked goods in the morning. I like the crunch. I like the cold milk. I give it up only reluctantly. Between breakfast and the Big Meal I drink lots of water and eat only fruits and vegetables. No cheating. Not one bite of anything else. It is not realistic for me to not eat anything from morning until the Big Meal, but I can ensure that I am good and hungry for it by only eating fruits and vegetables.
Then, when the Big Meal comes, I am very hungry and I feel no obligation to eat any vegetables I don’t want. I eat only the good stuff (by which I mean yummy). I don’t overdo it but I do enjoy myself and consume more than I need. I have a good time.
Let me be clear, I do this not because I think it is healthy but because it helps me enjoy the Big Meal. Being very hungry helps. Not filling up with vegetables at the Big Meal lets me enjoy the other, special stuff.