What's in your sandwich? U.S. wants you to know

The daily menu board is set up in the dining room at the Biggest Loser Resort in Ivins, Utah September 6, 2010.

WASHINGTON/LOS ANGELES (Reuters) - Restaurant chains will have to tell you how many calories are in your sandwich, your milk shake and even your bag of chips by the middle of next year as part of the U.S. government's fight against obesity.

The Food and Drug Administration said on Friday that final rules requiring restaurants and retail food companies to divulge nutritional and calorie information are expected to be issued by the end of 2011.

It proposed that the rules, pertaining to food and drinks sold from menus and display cases, would become effective six months later.

In a country where two out of every three people are overweight or obese, the government hopes to influence food choices and ultimately lower healthcare costs.

Restaurants with 20 or more locations like McDonald's Corp and Yum Brands Inc, operator of the KFC, Taco Bell and Pizza Hut fast-food chains, would be affected, as would retail food outlets.

The rules, part of the U.S. healthcare law passed in March 2010, would go into effect for vending machine operators one year after publication, according to the FDA proposal. Calorie and nutritional information would have to be displayed close to food items in vending machines or near selection buttons.

Restaurant industry groups had fought against local efforts to require calorie disclosure, arguing it would raise operating costs. But in New York City, the first U.S. city to require calorie count displays, 15 percent of people who used the information said they ate about 106 fewer calories at lunch, according to city health statistics.

On Friday, the National Restaurant Association said it would provide detailed comments to the FDA to ensure that restaurants get enough time to make the changes.

The FDA is seeking public comment on the proposed menu labeling until June 6 and on vending machines until July 5.

Movie theaters, airplanes, bowling alleys, and other establishments whose primary purpose is not to sell food would not be subject to the proposed regulations, the FDA said.

(Reporting by Esha Dey; editing by Gunna Dickson)