WASHINGTON — Counting your calories will become easier under new government rules requiring chain restaurants, supermarkets, convenience stores – and even movie theaters, amusement parks and vending machines – to post the calorie content of food “clearly and conspicuously” on their menus.

The long-delayed rules announced by the Food and Drug Administration Tuesday apply to businesses with 20 or more locations and give them until November 2015 to comply.

The idea is that people may pass on that bacon double cheeseburger at a chain restaurant, hot dog at a gas station or large popcorn at the movie theater if they know that it has hundreds of calories. Beverages are included, and alcohol will be labeled if drinks are listed on the menu.

“Americans eat and drink about one-third of their calories away from home and people today expect clear information about the products they consume,” said FDA Commissioner Margaret Hamburg. She said the effort is just one way that Americans can combat obesity.

The menus and menu boards will tell diners that a 2,000-calorie diet is used as the basis for daily nutrition, noting that individual calorie needs may vary. Additional nutritional information beyond calories, including sodium, fats, sugar and other items, must be available upon request.

The rules deal a blow to the grocery and convenience store industries, which have lobbied hard to be completely exempted since the menu labels became law in 2010 as a part of health overhaul. Even before the new rules were announced, Republicans in Congress had expressed concern that they would be too burdensome for businesses.

The law came together when the restaurant industry agreed to the labeling in an effort to dodge a growing patchwork of city and state rules. But supermarkets, convenience stores and many other retailers that sell prepared food said they wanted no part of it.

The FDA issued proposed rules in 2011 that included supermarkets and convenience stores but excluded movie theaters.

The final rules being released Tuesday include all of them.

The restaurant industry, along with nutrition and consumer advocates, has said that any business that sells prepared foods should be included. If a rotisserie chicken is labeled with a calorie count at a takeout restaurant, it should be labeled at a grocery store, they argued.

Representatives for the supermarket industry have said it could cost them up to a billion dollars to put the rules in place – costs that would be passed on to consumers. They said the rules could cover thousands of items in each store, unlike restaurants, which typically have fewer items.

To assuage some of their concerns in the final rules, FDA excluded prepared foods that are typically intended for more than one person to eat and require more preparation, like deli meats, cheeses or bulk deli salads.

But a sandwich for sale at the same counter would have to have a calorie label nearby, and the majority of prepared foods in the grocery store will have to be labeled – from the salad bar to the hot food bar to cookies and birthday cakes in the bakery.