I have 2 cats, brother and sister, that are about 3 years old. I've grown up with cats all of my life, so I'm not concerned with the female who seems to be at a comfortable weight. The male is the one I'm concerned about. I think he weighs about 20+ pounds. He is a very large cat and also has long hair so he looks equal to a small dog. We used to joke about how his fur made him look very large, but now his body has caught up. Currently I use Purina Cat Chow, but I'm thinking about switching to something else. At the time being I live in a small place until June so I try to get him to exercise as much as possible. What else can I do for my cat?