UPDATE 1-US FDA to give restaurants more time on calorie counts

* FDA plans to delay enforcement of new menu rules

* Calories, other details required on menus

* Vending machines must also carry nutrition information (Adds details on requirements, comment from industry and CSPI)

WASHINGTON, Aug 24 (Reuters) - U.S. health regulators plan to give restaurant companies more time to comply with new rules that require clear calorie and nutritional information on menus.

Under the healthcare law passed in March, restaurants must clearly post calories and other nutrition details on their menus. The rules target restaurants with 20 or more locations, as well as other retail food outlets, and would affect huge national chains like McDonald's Corp MCD.N and Yum Brands Inc YUM.N, the operator of the KFC, Taco Bell and Pizza Hut fast-food chains.

The U.S. Food and Drug Administration has until March 2011 to put these rules into effect. But the agency said on Tuesday it would hold off on enforcing them for an unspecified time period so that companies could make the changes. It also asked for public comment on how long to refrain from enforcement.

Other companies likely to be affected by the new menu rules include Starbucks Corp SBUX.O, Olive Garden and Red Lobster owner Darden Restaurants Inc DRI.N, and IHOP and Applebee's parent DineEquity Inc <DIN.N.

Consumer advocates and some public health experts praise menu disclosures as a way to help diners make better food choices and, hopefully, to help improve health in a nation where two out of three people are overweight or obese.

“It’s going to help a lot of people watch their waistlines and calories,” said Margo Wootan, a director of nutrition policy for the Center for Science in the Public Interest.

Some industry critics have argued that menu labeling rules -- particularly if they were to involve a patchwork of different state and local laws -- would be a burden that would add operating costs.

Dan Roehl, public affairs specialist for the National Restaurant Association, which often takes the lead on regulatory issues, said the industry supports a national standard for disclosing nutrition information.

“Once FDA completes the regulatory process, the industry will have all it needs to comply with the federal law ... It’s important for our members to know what they need to do,” Roehl said.

Privately-held Subway for years has prominently displayed calorie counts in its restaurants. The sandwich chain also suggests ways for customers to reduce calories by eliminating richer ingredients like cheese and mayonnaise.

Panera Bread Co PNRA.O in March began adding calorie counts to its menu boards ahead of the national requirements.

Nevertheless, most major chains have resisted posting such information without legislation and the threat of fines. Several states, counties and cities have proposed or passed laws requiring menu labeling, but only a handful -- including New York City -- have put them into effect.

The FDA posted the draft guidelines on its websitehere (Reporting by Susan Heavey, additional reporting by Lisa Baertlein; editing by Gerald E. McCormick, Bernard Orr)