A doctor and a consumer group have sued KFC in an effort to stop the chicken chain from cooking with high-fat partially hydrogenated oil. Dr. Arthur Hoyte, a retired physician from Rockville, Md., and the Center for Science in the Public Interest, want a judge to order Kentucky Fried Chicken to use other types of cooking oils or make sure customers know about trans fat content immediately before they make a purchase. KFC spokeswoman Laurie Schalow called the lawsuit frivolous and said the company will fight it in court. Schalow said KFC is looking at using other types of oil...