Q. My cat has gained a lot of weight: 26 lbs. He drinks tons of water and sleeps all the time. He won't play with the other cat like before. Help!
A. Firstly you need to have him checked over by your vet and some blood tests done to rule out any medical problems. Diabetes is ringing alarm bells in my head. If these are ruled out then it will be a matter of changing onto a strict diet food and trying different ways of exercise such as chasing games or feeding from a feeding ball. This can be set as an official weight loss program by your veterinary nurse with regular weigh ins. Definitely see your vet for blood tests first though.