Taco Bell will be the latest fast-food chain to cut artery-clogging trans fats from cooking oils in its U.S. restaurants, the company announced Thursday.

The nation's largest seller of quick service Mexican-style foods uses the oils to fry its nachos, taco salad shells, potatoes, chalupa shells and other items.

"This is something we've been working on for over two years, and we just believe it's the right thing and the right changes to make in our products," said Warren Widicus, Taco Bell's chief food innovation officer.

Widicus said the change means 15 Taco Bell menu items will contain no trans fats, including the Crunchy Beef Taco, the Taco Supreme, some chalupas and cinnamon twists. He said some items, like the Grilled Stuft Burrito, will still contain some trans fat.

Trans fats, which have been linked to heart disease, are being removed from many fast food kitchens nationwide as companies try to improve offerings to health-conscious diners. Wendy's International Inc. (WEN) and KFC have already switched to a zero-trans fat oil, and McDonald's Corp. (MCD) is considering the change.

Taco Bell is owned by Louisville, Ky.-based Yum Brands Inc. (YUM), which is also the parent of Pizza Hut and KFC, which announced last month that it was switching to a non-trans fat oil.

Taco Bell said all 5,000 of its single-brand restaurants in the United States will change from a partially hydrogenated soybean oil to a trans fat-free canola oil by April. About 100 restaurants have already made the change. Restaurants that share a roof with another Yum-owned eatery, like KFC, will use trans fat-free soybean oil, the company said.

Taco Bell began searching for a substitute two years ago with blind consumer taste tests.

"We conducted a tremendous amount of consumer research to make this the right choice for our customers," said Emil J. Brolick, Taco Bell's president.

Widicus said the oil switch is the latest effort by the fast food chain to create healthier menu items. In 2003, Taco Bell began offering a "fresco style" option that replace cheese and cream-based sauces with salsa.

When eaten, artificial trans fats significantly raise the level of so-called "bad" cholesterol in the blood, clogging arteries and causing heart disease. Researchers at Harvard's School of Public Health estimated that trans fats contribute to 30,000 U.S. deaths a year.

"This is great step forward. It will make Taco Bell's fried products significantly healthier," said Michael F. Jacobson, director of the Center for Science in the Public Interest, a Washington-based nonprofit that advocates food nutrition. The group called for KFC to switch to a healthier cooking oil for its chicken in a lawsuit earlier this year. The suit has been dropped.

Taco Bell restaurants outside the U.S. are also considering a switch to a non-trans fat cooking oil, said Taco Bell spokesman Rob Poetsch.

The Food and Drug Administration says artificial trans fat is so common that the average American eats 4.7 pounds of it a year. Movements in New York and Chicago are pushing for a ban on trans fats, and New York's health commissioner has called them "invisible and dangerous."