NEW YORK - A NEW rule requiring New York chain restaurants to post calorie information on their menus took effect on Friday, marking a first for a United States city.

Starting on Saturday, health inspectors can slap fines of up to US$2,000 (S$2,700) on fast-food and casual-dining chains if calorie counts are not displayed on their menus in the same font and format as the name or price of food items.

The move follows the city's 2003 ban on public smoking and a ban on artery-clogging trans fats that began on July 1.

'I'm going to eat whatever I'm going to eat,' said Ms Erika Roberson, 19, leaving an Applebee's restaurant in Brooklyn.

The rule affects such restaurants as McDonald's; Burger King; Applebee's, operated by DineEquity; Dunkin Donuts; Starbucks and Subway.

'I'm for it. I don't think the average person has any idea what they're eating,' said Ms Amanda Goodwin, 33, a school administrator.

Analysts said they did not expect the rule to have much impact on consumer habits.

'I'd be shocked if consumers weren't already aware that when they're eating in a fast-food restaurant, the cheeseburgers and fries and fountain drinks, are not healthy,' said Morningstar analyst John Owens.

'People don't go to McDonald's for a healthy lunch. They go for a fast-food burger and fries,' he said.

A city study last year found 30 per cent of New Yorkers were consuming more than 1,000 calories at lunchtime.

Officials say the rule could prevent at least 150,000 New Yorkers from becoming obese and prevent at least 30,000 from developing diabetes over the next five years.

The health code provision, which affects businesses with at least 15 establishments nationwide, was delayed when the New York State Restaurant Association fought back in court.

In April a federal judge upheld the rule and the restaurant association appealed, but a higher court refused to delay the regulation further. -- REUTERS