His bloodwork came back while I was in the hospital. It all came back fine, no thyroid issues, nothing. His vet says it looks great!

Hmm...how come he's lost so much weight then? The vet thinks he was given a poor diet in his old home, so he porked out and that's all he did. She said that now that he's on a proper diet and has attention, he's gotten down to his healthy weight.

That's good news, it just seems to wierd to me. Have you ever had this type of thing happen?