system
Given the following post, respond as if you're commenting on Reddit:
human
If Superman, or any hero with super powers, stopped working out, would they lose the muscle mass?
gpt
Superman gets all his bodily needs from the yellow sun's radiation. He doesn't need to sleep for rest or eat for nutrition. However, he still does these things because he grew up as an earthling. It took him a while to get past the psychological barriers that he doesn't need food or even air.

I'd imagine that Superman's muscle mass and physique is from the sun's radiation providing him with necessary nutrients. If the sun also maximizes his muscle growth and minimizes putting on fat, then its possible for him to keep his muscle mass without working out.