NEW YORK (Reuters) - KFC on Monday said all 5,500 of its U.S. fried-chicken restaurants will switch to a cooking oil with no trans fat by the end of next April.

The company, a unit of Yum Brands Inc. , is also switching oils at its 786 restaurants in Canada.

With fast-food restaurants under increasing criticism that they contribute to obesity and the risk of heart disease, KFC joins hamburger chain Wendy's International Inc. in cutting out artery-clogging trans fats.