My Favorite....
It's high in calories, but....
Blue Bunny makes fat-free ice cream. To give it consistency, they use Sorbitol (sugar alcohol). On most people, if they eat more than a double serving, it has a diuretic effect.
Buy a half gallon, down at least half the tub and drink water. In no time you'll be spewing water out your hiney. The effect lasts between 24-48 hours. You actually have to dehydrate to stop it short-term so you can do stuff like sleep without constantly running to the can.