my fat cat

i put my cat on a diet about a month ago. he's still fat. why is he still fat? the vet doesnt understand why i can't reduce my pets weight.... i think he's eating out. i think he's getting friendly with the neighbors and eating their cat food. it's a mystery.... maybe he just needs to go for a jog 3 or 4 times a week. how do you motivate a cat to get in shape.... teach him little kitty crunches?
whenever he walks in the door he loudly demands food. i think he's addicted to food. i think he has a dependancy problem. he'll meow for food right after he's finished eating. maybe he really wants something else. maybe he needs a girlfriend. or maybe a boyfriend. i think maybe he's gay. maybe if he came out of the closet he would feel a sense of relief and would shed those extra pounds.
i have no answers.