LOUISVILLE, Ky. - Fried chicken restaurant chain KFC announced Monday all 5,500 of its U.S. restaurants have stopped frying chicken in artery-clogging trans fat.

The company said in October it was switching to a new soybean oil believed to be less likely to cause heart disease. "This idea is a positive one for consumers and we do expect it's going to really appeal to people and bring them into our stores," said James O'Reilly, KFC's chief marketing officer.

The zero grams trans fat items at KFC also include its potato wedges. Some of KFC's non-fried items still contain trans fat, including biscuits, pot pies, macaroni and cheese and some desserts. The company said it's working to remove trans fat from those items.

KFC said the change in cooking oils will not change how its fried chicken tastes.

Sister brand Taco Bell also said Monday its U.S. restaurants have completely switched to an oil with zero grams of trans fat. All 4,200 single-brand Taco Bells were converted to a canola oil and all 1,400 multibrand locations switched to a soybean oil, the fast food chain said.

There are 23 Taco Bell items that contain no trans fat, including the chicken and beef crunchy taco, grilled steak soft taco, chicken and steak Gordita Supreme and the chicken and steak Chalupa Supreme. Taco Bell said it's working to remove all trans fat from all its ingredients.

The two chains are subsidiaries of Louisville-based Yum Brands Inc., whose brands also include Pizza Hut, Long John Silver's and A&W All-American Food Restaurants.

The announcements come amid a push to rid diets of trans fat. New York City and Philadelphia have required restaurants to phase out trans fat by next year and bills to restrict or ban trans fat in restaurants or school cafeterias have been introduced in a number of states.

Doctors say trans fat - listed on food labels as partially hydrogenated vegetable oil - can raise bad cholesterol and lower healthy cholesterol.

Other companies including Wendy's International Inc., Starbucks Corp., McDonald's Corp. and Burger King Holdings Inc. have said they will phase out trans fat from their products.

Denmark is the only country to have sharply limited trans fats, passing a law in 2003 making it illegal for any food to contain more than two per cent trans fat. Canada is looking at similar legislation and the Netherlands has encouraged voluntary labelling.