system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If muscle is lost during severe dieting, is it actually "lost" as in gone, needing to be rebuilt from nothing? Or are there remnants that simply need to be repaired?
gpt
No. Your muscles are never really "gone". As in, you'll still have your muscle strands and muscle groups. When dieting, the muscle strands just get thinner, and you lose muscle mass. When working out, the muscle strands get thicker, and you gain muscle mass.

You never really gain or lose muscle strands. The strands just get bigger or smaller.