A hidden world of chemistry explains why butter and margarine can transform the same recipe in surprisingly different ways. Credit: Shutterstock My mother loves butter. It is the primary fat I ate growing up. She smeared it on any kind of bread, potatoes, nut rolls or coffeecake. She baked with it exclusively. When I was studying nutrition in college, I had a teaching assistant who recommended margarine over butter. I was shocked – and wondered about the difference between the two. It was one