The Fit Recovery Cycling Dictionary defines “Fat” thusly:
What a bicycle runs on.
Notice there isn’t any on me? Or maybe let’s just say that there’s a healthy amount of fat on me. Yes, let’s go with that. The point is, there isn’t much on me because my bicycle runs on it. I ride my bicycle(s) a lot and eat a good, balanced diet. Therefore, no fat.
It’s not rocket science, though some try to make it out as such.