NEW YORK (AP):

New York City's ban on trans fat cooking oils in all city restaurants, an idea that gave chefs indigestion when first proposed, seems to be going surprisingly smoothly. Across the city, most fast food chains say they have already made the switch days before the Sunday, July 1 deadline.

The same cannot be said for a second restaurant rule also taking effect: the posting of calories on fast-food menus. The major chains are defying that regulation and hope a lawsuit will overturn it.

The city does not plan to fine anyone for violating either rule until Oct. 1.

Major health victory

Still, the trans fat overhaul is seen as a major victory by health advocates. Trans fats, found in partially hydrogenated vegetable oils, clog arteries and contribute to heart disease. But they are also cheaper and have a longer shelf life, so the industry at first resisted dumping them.

That began to change last winter.

Cooking oil companies had already ramped up production of trans-fa Restaurant supply companies began stocking kitchens with replacement products.

Big fast food chains that relied heavily on the old oils, from Burger King to Carl's Jr. to Kentucky Fried Chicken, announced they would eliminate the stuff from their fryers nationwide.

Even McDonald's, which had anguished over the potential impact on its french fries, said its phase-in of the new oils in thousands of restaurants has gone unnoticed by customers.

"The transition has been absolutely seamless," said spokesman Walt Riker.

While the city health department has not finished compiling results of a recent survey on oil use, there is evidence that smaller restaurants are ready too.

A special help line, set up by the city for chefs trying to reform their kitchens, has been lightly used.

The ease of the switch to zero-trans fat oils may have been aided by the behind-the-scenes work of seed and oil companies.