A cat I know fell in love with rowing. He obsesses over it. He has rowing shirts, he read stories and watches movings about it, he's looked up and completed training regimens and exercises. He's lost about 80lbs. I'll see if I can get some pics with his face blurred out (I'll have to ask him personally). But it's something he loves. He doesn't care about the look or even the weight loss, those just happen to be the caveats of being into it. He doesn't diet but he eats according to what he's going to do, whether it's a sprint or a long session.
It was something he tried once and he was hooked and it works for him. He's probably been doing it for close to 2 years now.