Thank you for adopting an FD kitty!
I have a fatty too =) Tugger is 19 pounds, down from 25. I do exactly what Venita suggested, Tugger loves his food and will usually race down the hallway from the bedroom to the kitchen, trying to beat me there ;-) So I make several trips back and forth at meal time (I don't even need the food in my hand, there just needs to be none in the kitchen to eat lol) he races from the kitchen to the bedroom if I "forget" to put the food down then when I head back in the kitchen direction he goes racing back :twisted: We do this about four times a day (we do mini-meals instead of two big meals) plus he also runs away from the dogs (I have great danes) when they get hyper.
I also have a feather ona stick toy that he adores and lots of floor space in the living room... so I get that out once a day and get him moving. Some days are lazy days, he won't get moving for anything but the dogs, but they have daily zoomies so even on his lazy days he gets a little exercise
Getting him off the dry food and eating a good low carb canned diet has also helped a lot. He hasn't lost weight yet but he's slimmed down a hair. His belly used to be round and hard like a little beer keg but now it's sticking out less on the sides and he's getting saggy belly skin. He's grooming himself a bit more too, though he still can't do his whole self. I need to get at least three or four more pounds off him to see that again probably.
It's taken some time, but he's getting there =) I'd say start with getting him to chase his food, you might have to walk quickly or even jog a bit to get him moving, your drag a string behind you a few times to get him interested then give the food as a reward for chasing it/you. I didn't have to teach Tugger to move for his food, I just started using what he normally does

Good luck!!