Wager on losing weight?

How much weight would you be willing to lose, if someone asked 'wanna' bet on it?'" Making a wager can trim the fat without starving your wallet.

How many times have your heard it, exercise and healthy eating are the best way to lose weight?

Easier said than done. But how about putting some money on the table to make it interesting?

Health-conscious Americans are now turning to websites to make their weight loss wagers.

Mary Lou Wehrli and her brother Grant are using FatBet.com to shed about twenty pounds each. What is at stake?

They post their weight at least once a week on the website, and occasionally taunt each other on FatBet's blogs.

Users say the teasing and the tempting are all part of the fun.

Both weighing in and paying up depend on the honor system.

MakeMoneyLosingWeight.com is another diet betting website that is free to users.

And at a third website, StickK.com, when you place a wager, you sign a commitment contract, hand over your credit card number, and each week that you don't meet your goal, you are charged.

When you lose a bet, you choose where the money goes: to a competitor, a charity, or what they call an "anti-charity," an organization you oppose.

But diet betting might not work for everyone, says Elisa Zied, of the American Dietetic Association.

A recent study by the Univeristy of Pennsylvania and the Department of Veterans Affairs Medical Center in Philadelphia confirmed "cha-ching," with an element of risk, can be a strong motivator for losing weight. Researchers also concluded, the effect of short term rewards on long-term behavior still needs to be studied.