"Dig in," said the king, poking Milo with his elbow and looking disapprovingly at his plate. "I can't say that I think much of your choice."
"I didn't know that I was going to have to eat my words," objected Milo.
"Of course, of course, everyone here does," the king grunted. "You should have made a tastier speech."
Norton Juster - The Phantom Tollbooth
I was in this play in 5th grade, as the Spelling Bee, it was fun (except for a boy I hated purposely screwing up my lines). Anyway, what happens in this part is that in this world you eat for dinner the words you say, like if you said "pudding...cake...chicken..." etc that's what your words would taste like. Milo didn't realize this and gave a little speech, and had to eat those words, which weren't too tasty. The point is to watch what you say. There's another saying somewhere like "Watch your words, you might have to eat them." or something like that.