A nutrition advocacy group sued hamburger chain Burger King Holdings Inc. (BKC) Wednesday over the restaurant chain's use of frying oil that contains artery-clogging trans fats.

In court papers, the Center for Science in the Public Interest said Burger King is the only leading restaurant chain that has not yet committed to eliminate trans fats from its menu.

A Burger King spokesman was not immediately available for comment.

Trans fat increases the low-density lipoprotein — so-called bad cholesterol — in food, and U.S. health officials have advised Americans to consume as little trans fat as possible.

Several chains, including Wendy's International Inc. , Yum Brands Inc.'s (YUM) KFC and Taco Bell units, Starbucks Corp. (SBUX) and McDonald's Corp. (MCD) have either already made the switch to healthier oils or have said they are working on finding a replacement.