Want to fatten your wallet and lose weight? New websites let you bet that you'll meet your goals – and earn money when you succeed. DietBet.com lets you bet against your pals: Those who reach their target weights by the last weigh-in win money... In general, people lose more weight when there is money on the line, a recent analysis of research from Cornell University found. Take Nat Walker, 50, who recently competed with a group on DietBet.com. He lost more than 10 pounds and won his challenge. "The financial incentive was there," says the project manager from Burlington, Connecticut. "It gave me an absolute goal of where I needed to be in28 days, and it was extremely motivating.

Diet bets have become a hot trend online, in gyms, and as informal wagers between friends—and they work. One study found that dieters who stood to lose money if they didn't shed weight were five times more likely to reach their weight-loss goal than those with no financial stake. Half of the bettors shed 16 pounds in 16 weeks, versus only 10.5 percent of the non-bettors. Read the full article.

32-inch pizza, 3 minutes to spare, and a lot of beverages, the "Last Supper" was a definite eating contest. These eaters are the most competitive people out there -- you give them a competition, even if it's dieting, they'll do it!" Jamie Rosen, DietBet founder said. "Our business is about having fun while losing weight. These guys were totally up for it. Read the full article.

Quitters and daydreamers, take heart! New web services don't just help keep you focused on your goals. They pay you to stick to them, and they pick your pocket if you don't. Result: You feel more committed to your ambitions, users say, and the odds that you'll achieve them rise. Other sites have a more narrow focus. Dietbet and HealthyWage, for example, are specific to people wanting to lose weight. Read the full article.

"It's the ultimate challenge for competitive eaters everywhere: don't eat." Six "All Pro Eaters" vowed to go on a one-month diet on Friday, in an unusual competition that pits once-weighty gorgers against their own fat for a chance at $1,000. Whoever loses four percent of their weight over that month splits the pot. Read the full article.