Some bad habits, it seems, are easier to kick than others.

It took five years for Philadelphia City Council to agree on a smoking ban, but today - mere weeks after the idea was first proposed - council unanimously approved a bill banning trans fats from most dishes served by city restaurants.

In recent years nutritionists have vilified trans fats as a largely artificial, artery-clogging fat with no dietary benefits. Think Crisco or margarine: inexpensive, semi-solid fats with long shelf-lives.

Philadelphia's ban on the use of such products begins to take effect on Sept. 1, when restaurateurs will no longer be permitted to fry foods in trans fats or serve trans fat-based spreads. By Sept. 1, 2008, trans fats will be banned in all other types of food prepared in Philadelphia eateries. The ban will not apply to pre-packaged foods - such as a Tastykake Krimpet - sold in city stores and eateries.

Councilman Juan Ramos, who sponsored the bill, said it would have a clear and quantifiable impact on the health of Philadelphia residents.

"I expect as Philadelphia's food service establishments replace artificial trans fat with currently available heart-healthy alternatives the result could be as much as a six percent reduction in coronary heart disease events in our community," Ramos said.

New York City has already outlawed use of trans fats in restaurants, and 19 states are considering banning or restricting use of trans fats. Many restaurant chains and institutions - such as universities and school systems - have already done away with trans fats or sharply reduced their use.

Philadelphia's ban will be enforced by the Health Department, but it does not include penalties for violators. Ramos said he does not expect eateries to flout the law, and he said penalties could be created if they were later deemed necessary.

The bill defines food as trans fat free so long as they contain less than .5 grams of trans fat per serving.

Contact staff writer Patrick Kerkstra at 215-854-2827 or pkerkstra@phillynews.com.