Like it or not, as we age, our muscle cells are slowly exchanged, one by one, for fat cells. This process quickens when we injure a muscle, and an extreme form of this process is also seen in muscle-wasting diseases such as Duchenne muscular dystrophy (DMD). Now, scientists have shown that cellular antennae called cilia, found on fat-forming cells interspersed in muscle, play a key role in this muscle-to-fat transformation.