You have to see this to believe it. This video from CNN shows how a 31-pound cat is losing weight by walking on an underwater treadmill.
I wonder how they were able to get this cat to even stay in the water. I think my cat would lose more weight in the process of fighting to stay out of the water. I would also have to buy A LOT of bandaids before attempting it. In fact, I am pretty sure the cat in this YouTube video "saying no" to a bath is a close relative of my cat:
My first cat LOVED water. He'd actually get in the shower with me. So one day I said, let's fill the bath tub with water. The little guy swam around in it.