I've got a 16lb cat. He is huge but not chubby at all. I don't know where he got his giant gene because his sisters weigh in at around 7lbs.
I have a "fluffy" cat that is 14lbs. The vet gave us a lecture for 20 minutes on how bad of pet owners we were, and how we should give our pets up for adoption if we cannot "handle" them. We switched vets. Our problem is that we have outdoor/indoor cats, and outdoor only cats. The outdoors are free fed the cheaper food, and the indoors are portioned very balanced food. However, I know they all probably graze on the outside food. My neighbor also has a stray that he free feeds, and our other neighbor feeds another stray.