DietBet

DietBet is an online social dieting game that gives players the opportunity to win money through weight-loss competitions. Dietbetters play with friends and co-workers and put money into a pot; whoever reaches the goal by the end of four weeks wins the pot (or splits it). It's motivation through friendly competition, with real rewards. Founded by Jamie Rosen and launched in December of 2011, DietBet makes losing weight fun.