I too am a mom of an overweight cat. Montanna wieghted in at 22lbs.. but he is Maine Coone.. a big cat anyways.. but when we got him (11 years ago) he came with this huge stomach like he swallowed a football, and would eat anything, and lots of it.. for 8 years we tried everything.. diets, exercise.. finally we got this vet who came up with the best advice.. in a multi-cat household, feed the problem cat, and the others will adjust.. so we sent and bought Science Diet Light and a diet senoirs food..all the cats eat the same food... all my cats are very inactive.. sleep atleast 18 hours a day.. now two years later, Montanna is a slim 17 lbs.. (well as slim as a big guy can be) and is a lot more active, he also dosn't hang out around the food dish anymore.. but he does show up at the table looking for treats at dinner.. I give him very lean beef or chicken breast.. just alittle.. so he still feels special.. The other cats have adjusted and will eat more. I leave food out all day, I think they do feel more confident knowing the dish is always there and eat less..

Hope your guy can loose weight soon.. Montanns is happier being more active