City restaurants may get more time to rid their menus of trans fats after the health commissioner said the Bloomberg administration was almost certain to revise its proposed ban before the Board of Health meets next month.

Speaking at a Crain’s breakfast at the Waldorf-Astoria Hotel yesterday, the commissioner, Dr. Thomas Frieden, said the city has not decided on any changes, but he indicated the 18-month timetable for the phase-out of trans fat could be extended, and officials could add measures to assist businesses with the transition.

Restaurant industry leaders have opposed the proposal, saying the city is moving too quickly to force eateries to switch to healthier ingredients. Trans fat, considered by doctors to be the most dangerous form of unsaturated fat, is found in some cooking oils, shortening, and baked and processed goods.

“I do think there are transition difficulties for some places,” Dr. Frieden said. “We’re looking at a combination of timing issues, technical support issues, and phasing issues that we think will help deal with that as we move forward.”

The commissioner said he expected the Department of Health and Mental Hygiene to submit a revised plan to the 11-member Board of Health when it meets December 5. A vote is expected at that meeting.

Most health and nutrition organizations have supported the ban, but in a surprise move, the American Heart Association raised concerns that the city was going too fast.

The department is reviewing every one of the more than 2,000 pages of public comment it received on the trans fat ban, Dr. Frieden said. In a separate proposal, the city also wants to require some restaurants, mostly large chains, to display caloric data on menu boards.

While the commissioner opened the door to alterations, he defended the substance of the proposal, saying that in the administration’s experience, “regulation is simply by far the most effective way to achieve change.”

He also disputed claims by the restaurant industry that a ban is impractical because there is not enough supply of alternatives currently on the market. The five boroughs, Dr. Frieden noted, make up less than 3% of the population of America. “I think it’s okay if we’re first online for healthier food in New York City,” he said.

The executive vice president of the New York Restaurant Association, Charles Hunt, said he was encouraged by Dr. Frieden’s remarks. “I’m hoping there’s room for further negotiations or modifications.”

Dr. Frieden discouraged the City Council from passing its own bill to regulate trans fat, saying legislative action would only complicate things, including lawsuits that could be forthcoming from national chain restaurants. The chairman of the council’s Public Safety Committee, Peter Vallone Jr., said he planned to move forward with a bill anyway.