Wow! I thought my cats were big. I have 4 large male cats and they weigh as follows: Storm 14lbs, Sunny 11-12lbs, Cirrus 15lbs, and Sky 12-13lbs. As long as he's healthy and is able to clean himself, I wouldn't be too worried about his weight. I had to stop free feeding mine because Cirrus and Sky were gaining too much weight.

Now I feed them 1/4 cup of dry food 2 times a day or 1/2 cup total of dry food per cat a day. My vet recommended that I put them on a diet before any problems occurred. At first they weren't very happy about it but now they've learned the routine.