First and foremost, popcorn. With a big tub of soda, of course.
Well, according to an analysis by the Center for Science in the Public Interest:
It's hard to picture someone mindlessly ingesting three McDonald's Quarter Pounders with 12 pats of butter while watching a movie. But according to new laboratory analyses commissioned by the nonprofit Center for Science in the Public Interest, that food is nutritionally comparable to what you’d find in a medium popcorn and soda combo at Regal, the country’s biggest movie theater chain: 1,610 calories and three days’ worth — 60 grams — of saturated fat.
That's a hefty caloric price to pay for what most people think of as a snack.