How can I get my lazy cat to exercise?

[ALM]

I have a cat around the age of 2. He is slightly overweight according to my vet. I have put him on a strict diet that works well for him, and he has lost a bit of weight, but he's just so darn lazy that its hard to keep him at a healthy weight. He has lots of different toys, including ones that require me to play with him, but he just doesn't seem interested. He sometimes plays with toys that he can just lay down and chew on. He'll also run after a laser or jump for his fishing rod toy, but only for a minute or two then he lays back down. Other than those couple extra pounds, he's healthy. I don't know what I can do to get him motivated. I even got another cat for him to run around with. They have a great time sometimes, but most of the time my bigger cat just lays and watches the little one play. Does anyone have any suggestions for toys that might get him moving, or something I can do? Any help would be great! Thanks!