The days are officially numbered for trans fat in New York restaurants, although some foods will get to keep it longer than others.

City eateries will have an extra year to expunge the artery-clogging chemicals from baked and deep-fried foods like doughnuts and churros under a revised proposal unanimously approved by the Board of Health yesterday.

But changes to the plan made by the Bloomberg administration have not satisfied the restaurant industry, and officials said lawsuits challenging the new regulations are likely. The industry is also opposed to a plan enacted yesterday that would require many chain restaurants to prominently display calorie information on menus; the city altered that plan as well, allowing for more flexibility in compliance.

The 11-member health board approved the trans fat ban with little debate, making New York the first major American locality to restrict an ingredient that doctors and nutritionists say increases the risk of heart disease and strokes, leading to thousands of deaths every year. Artificial trans fats, which are found in many frying oils and shortenings, are widely considered the most dangerous kind of fat because they increase levels of “bad” cholesterol while reducing “good” cholesterol.

The move came over industry complaints of overregulation and objections that a low supply of alternatives would force restaurants to assume increased costs or turn to oils and shortenings that are high in unhealthy saturated fats. The Bloomberg administration rejected those claims, and the Board of Health agreed.

“What we’re talking about is a healthy oil change,” the city’s health commissioner, Dr. Thomas Frieden, said. “That can be made with no change in the taste of food, the quality of food, and the cost of food.”

Dr. Frieden said that despite opposition from the restaurant industry, the more than 2,200 public comments were overwhelmingly favorable. “There was essentially unanimous agreement — which is new — that trans fats should be removed from our food supply,” he said. The American Heart Association, which initially opposed the timetable of the city’s proposal as too ambitious, said yesterday that it supported the revised plan.

Mayor Bloomberg, who has left open the possibility of a 2008 presidential run, has made public health one of his signature issues. A billionaire businessman, the mayor supports public health research with his philanthropy, and, in his first term, he implemented a sweeping ban on smoking in the city’s restaurants and bars.

A switch to oils high in saturated fat would be better than nothing, Dr. Frieden said. “If you replace trans fats with saturated fats, you still get a health benefit,” he said. “It’s not as big a health benefit as if you replace them with healthier oils, but you still get a health benefit.”

Responding to industry concerns, the city extended the timetable for phasing out trans fats. Restaurants must switch ingredients for frying oils and spreads by July 1, 2007, but they have until July 1, 2008, to replace trans fats in all other products. Dr. Frieden acknowledged that while trans fat does not affect taste, it does alter the texture of deep-fried foods that use yeast dough, such as doughnuts, and restaurants may need more time to come up with suitable alternatives.

The city is also adding a three-month grace period during which it will not assess fines, and it will create a training program and a helpline to assist restaurants making the change.

The revisions to the original proposal were not enough, the executive vice president of the New York State Restaurant Association, Charles Hunt, said. “We’re disappointed that we haven’t been given more time to do this,” he said. Mr. Hunt said he didn’t know what his next move would be but that the association was exploring its options.

Dr. Frieden said the city expected to “withstand any legal challenge.”

The Bloomberg administration also slightly relaxed its plan to force some restaurants to post calorie information on menu boards. The regulation requires eateries that have standardized menus and that already publicize nutritional information — almost exclusively large chains — to display calorie amounts at the “point of purchase.” The new plan approved yesterday allows restaurants to come up with alternative ways to post that data, as long as consumers can clearly see it before they decide to pay for their French fries or Whoppers. The rule applies to only about 10% of the city’s 24,000 restaurants.

“I don’t think it’s significant at all,” a spokesman for the National Restaurant Association, Daniel Fleshler, said of the change. “It still punishes restaurants that provide nutritional information. It’s a serious disincentive.”

In another revision, the city will not be able to shut down restaurants that flout the new rules. Officials will assess fines for violations, but they will not count against a restaurant’s pass/fail sanitation inspections.

The administration first proposed the trans fat ban in September, prompting some national chains, including Kentucky Fried Chicken and Taco Bell, to speed up plans to switch to healthier oils. Other chains that still use trans fat said yesterday they would try to comply with the city prohibition. In a statement, McDonald’s said it was “very encouraged” by results of its testing of new frying oils. “However, we are not yet prepared to announce a national rollout for an alternative oil blend,” the statement said.

Some City Council members complained that the administration had bypassed the legislature by enacting its ban through the independent Board of Health. Seeking to avoid a battle with the administration, Council Member Peter Vallone Jr. has said he would introduce a bill to codify whatever rules the board approves.