Being a compulsive gambler is a bad enough character flaw. Being 50 pounds overweight and not having the motivation to do anything about it just makes things so much worse. Lucky for you, there's someone out there looking to serve exactly your kind of people. Presenting, Lose It or Lose It.
A web-based service, it uses gambling as a motivation to lose weight. Instead of wagering on horses or sporting events, though, you put money on your own weight loss goals. Keep meeting them and your money stays fine. Get off track and you could end up losing all the cash you put on the line.
Lose It Or Lose It lets you design your own 10-week weight loss program, which will include depositing money as "collateral," just to show how much faith you actually have in your own resolve. Any bet from $100 to $5,000 will be accepted. If you meet your goals, you get your entire money back and you lose weight (you don't actually win any money, but you do get a healthier body). If you don't, let's just say that someone's profited off your failure to stay in shape yet again.
Every week, you're supposed to submit a photo of yourself on a weighing scale with your current weight clearly visible. If you meet your target weight loss (you can set it in your program), you're good. If you don't, they'll deduct an automatic 5% from your wager. Since the verification isn't in person, you can cheat all you want. However, the service does reserve the right to call you on fake weigh-in pictures (e.g. bad Photoshop jobs) and will deduct money accordingly.
You can check Lose It or Lose It for the rest of the rules (and the official statement that it isn't, technically, gambling). Personally, we'd suggest letting the holidays pass before putting a wager - betting on losing weight with Christmas right around the corner is, typically, a losing proposition.