PS - Are you able to let him out where you live? If not, maybe you could play toss & fetch with him sometime to give him some exercise. My cat likes to. I put plastic half gallon milk caps on the back of my hand and flick them with my finger and they fly 2 or 3 rooms away and Luke chases after them, carries them back in his mouth, and drops them at my feet so we can play some more.
Sometimes I feel sorry for my cat. All his life is is walking from the front of the house to the rear and back, and looking out windows at each end, maybe seeing another cat once in a while, birds, etc.. I can't let him out here - too much traffic and too dangerous. I built a 5x10' fenced in enclosure that he likes to go out into in good weather, but Winter isn't far away.