it's science. eat less pizza
230 pound hemmy burns around 2500 calories a day if he sits around all day and doesn't exert himself physically. That means that if he consumes 2000 calories or less a day then he will lose a pound a week. If he pumps iron for an hour or plays basketball for an hour then he burns an extra 500-600 calories that day and can eat an extra 500 or so calories and still be on track.
It doesn't matter what you eat. If he ate 2000 calories of pizza every day(and only pizza), he would lose the weight. He wouldn't be very healthy but the weight would drop.
BTW, 2000 calories of pizza is like 5-6 slices of a large pizza hut pepperoni a day.