When I was 17-19, I took spiro (no E) but quit due to feeling weak. I took it so I could stop masculinizing, if it was possible. I don't know what I would look like if I never took it. The damage was already done though.
Anyways, I reckon it's the muscles dissolving... people were telling me I was looking good, losing weight and all that. I think once 100% of the muscles are gone, you'll stop losing weight.
I'm not a doctor, but it could be bone loss too if the E isn't at the right levels.