They used to be made with lard, which is animal fat! All you kids saying eew!, most sweets are or were made with animal fat! In the mid-1990s, health concerns prompted Nabisco to replace the lard in the filling with trans fat. Starting in January 2006, Oreo cookies replaced the trans fat in the cookie with non-hydrogenated vegetable oil. * BTW For everyone saying eew! JELLO is made with gelatin which is derived from the collagen inside animals' skin and bones.