Eating most anything in regular theatre seats other than something like a candy bar is really awkward. Once (and only once) I got a drink during intermission and finished it during Act II. Then I spent the rest of the time awkwardly not sure where to put the empty cup. I didn't want to put it on the floor where someone, if not me, would wind up kicking it, etc. I didn't want to hold onto it the whole time. And I definitely didn't want to get up and find a place to throw it away.
If I feel I really need something during a show I'll bring a roll of Life Savers. No individual wrappers, pretty easy to just take one out of the package in my pocket and that's that.
