How long does it take before food is metabolized?

I work in a cinema, and often find myself revolted by the climate in the hall after a show. It just doesn't seem to add up how incredibly hot and humid it gets in there even when it isn't sold out. Being in High School, I'm very aquainted with the idea of being packed in like sardines for an hour and a half, and it never gets like that, even in the really crammed rooms. The only thing I could think of that would cause such a difference might be the food. I know people in arctic climates consume butter to stay warm through the night, but could those high calorie foods have those effects within the duration of a film?