I don't know about anyone else out there, but I constantly find myself making my characters eat some variation of whatever I'm eating.
Actually, I do know that I'm not the only one who does this. The Turkey City Lexicon calls this a type of Dischism: "The unwitting intrusion of the author’s physical surroundings, or the author’s own mental state, into the text of the story."
As mentioned above, I do this most often with food. I don't know if it can be called unwitting, exactly. I know I'm doing it, and hopefully it gives the characters a bit of authenticity. Sometimes these situations become character traits in and of themselves. I've got a girl in one story who is a burgeoning tea connoisseur; she loves tea and has an improbable level of knowledge about the drink. It's not a major plot point or anything like that, but before the plot came along and ruined her life, tea was her hobby. In most situations, of course, making these little intrusions into defining character traits would be ridiculous. In the same story as the tea girl, there's a character who likes beans. He has a great recipe for beans, and there's a scene where he's making those beans. But if I were to make him into some sort of bean-obsessed bean man, he would look a bit stupid. Obviously, there's a line that can be crossed.
I just thought of this now because I'm in the middle of making a cake, and surprise! I ended up giving someone cake in a story. I erased the scene a few minutes later, because it really made no sense for there to be cake in that situation. If I had been working on a more whimsical fantasy, cake might have worked, but I wasn't. Surprise cake just didn't work in the slightly gritty setting that I was using.
And so sadly, I have learned that surprise cake isn't always a good thing.
By the way, I highly recommend that anyone who hasn't already read the Turkey City Lexicon linked above do so now; it's both hilarious and informative. If you find yourself repeatedly saying, "Hey, I do that!" it might be a good idea to think things over.