Well we have a tonne of stuff- homemades like Christmas Cake, mince pies, gingerbread house. Big meats, like gammon, turkey, beef, a whole poached salmon, a serrano ham leg. Several tins of sweets, many crisps/snacks, a massive cheeseboard, antipasti, fruits, salads, nuts. But... we have a huuuuuuge party on Boxing Day, where we open our house up to family, friends and neighbours, so we need lots of extra food and drink in.
On a personal level, I eat a special breakfast Xmas day (something like eggs benedict/eggs royale or maybe croissants/pastries, a roast with all the trimmings, plus Christmas pud on Xmas day. And then for as long as I can string it out, I eat cheese and biscuits, cold meats/fish, salad and pickles for as long as I can until it runs out or is past its best. Perhaps the odd mince pie or a few quality street, but I don't have a massively sweet tooth, so not really much of the sweet stuff. So I eat differently, but not necessarily worse, mostly it's about me not having to cook for a few days!