Absolute rubbish. Muscle is capillarised and contributes to work obviously. If you have muscles trained specifically for your activity they add to your economy/efficiency. Fat is dead weight. I've always gotta laugh when I hear boxers/boxing fans talk about these matters, somebody says something stupid and it gets passed down generations.
lol, is this simply just a lousy attempt to passively hype up this guy? Simple answer to the thread question: Look at the current champions of each weight division - 'nuff said