Before you buy a ticket, turn around and go home.
As a kid in the 1960s my parents would send us to the movies with bags of our own home-popped popcorn. I suspect they don't want you bringing your own food these days. I have not gone to a movie theater since the late 1980s when I saw Earnest Saves Christmas. Have watched a dozen or so movies on the computer from DVDs since.I was going to say something like that. At the very least don't pay their silly prices for snacks. Most people can go a couple of hours without consuming 5000 calories worth of chips, candy and nachos.