What size of Frontline/Advantage do you even put on a 30 pound cat? If you go by weight.. is there one for a 30 pounder? Yes, he needs to be on light food and loose some weight. Encouraged to play and get some excercize and get some of that weight off. I don't understand why some pet owners still thing the bigger, the better when it is so unhealthy. Make sure your babies are up to date on their flea treatment since he will sure bring them into your house.