system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: Why do muscles atrophy after extended periods without use?

The human body is remarkably efficient at self-preserving and maintaining important parts of the body, like the heart or liver. Why do our muscles deteriorate?
gpt
They are deemed unnecessary. Imagine a huge corporation that has an entire department running without any actual tasks. After a while they'll decide that there is no point wasting the money on them by paying for doing nothing so they let go of most of the department.