KFC's mashed potatoes and gravy is probably the chain's most iconic side. Although this dish has been on the KFC menus for many years, the mashed potatoes and gravy is one of the things you really, really want to steer clear from next time you're at KFC. The mashed potatoes and gravy is actually deep fried, and the oil is anything but fresh. Some KFC employees even said that the oil is often used for 12 consistent hours, and the contents at the bottom of the fryer would become a black solution dripping in fat.