The use of different oils in making fries

McDonald's used to make their fries in beef grease but now other restaurants openly use tallow, duck fat, and vegetable oils. In the past, there was a misconception that saturated fat from animals was unhealthy, leading to an emphasis on the use of partially hydrogenated vegetable oils. However, these oils contain harmful trans fats, which have led to their effective prohibition in foods. Fully hydrogenated oils are currently considered safe, but their long-term status may still be subject to change.