LAS VEGAS — Adam Aron, the chief executive of AMC Theaters, the largest multiplex chain in the world, sat in a hotel suite here last month and sang the praises of a new menu item he called “the Bavarian Beast.”

It’s a pound-and-a-half salted pretzel the size of a steering wheel. “There’s also a new jalapeño-flavored Southwestern dog that’s to die for,” he said. But Mr. Aron was most effusive about another new AMC offering, a juicy chicken sandwich with waffles as buns.

“Sounds fattening just to hear it described,” he said with a smile, “let alone when you eat it.”

Popcorn, candy and soda? How quaint. The concession counter at your local AMC is about to turn into a full-fledged fast-food restaurant.

It’s part of a strategy to attract younger audiences and stay relevant in the streaming age of HBO Go, Netflix and Amazon Prime. While small theater companies like the 25-location Alamo Drafthouse have been offering full-restaurant cinemas for years — AMC itself already operates a 60-location chainlet of Dine-In Theaters — this effort will bring greatly expanded menus to more than 400 theaters in the United States.