I've got a skinny cat.
I have a cat, and I have a really hard time keeping weight on her. She's a really weird cat, to start out with. She's permanenetly stoned. She'll walk around the house, jumping head first into walls, carries things around, loves baths, and acts like she's had one too many experiences with catnip.
I've taken her to the vet (a cat clinic) about it, because I was worried that she might have some sort of health issue. All of her hormone levels look fine, she doesn't have any of the common (or uncommon) cat diseases, and she's spayed. There's no reason she should be skinny.
Granted, she's not emaciated, but she's a big cat and only weighs 7 lbs. I've tried multiple foods (not in fast succession), and she has no problem eating, quite the opposite. She'll eat anything and eats a lot, but she still doesn't gain weight.
I doubt there's anything to worry about since she's healthy, but I was wondering if anyone had any particular foods or other things that I (and the vet) might be missing to look for.