Dieters Bet On Their Own Weight Loss -- And Lose : Planet Money It's really, really hard to lose weight -- even if money is on the line.
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Dieters Bet On Their Own Weight Loss — And Lose

"When you look at a doughnut, it looks amazing right now." Salim Virji/Flickr hide caption

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Salim Virji/Flickr

Dieters who place bets on their own weight loss with a London bookie usually wind up losing, according to a recent analysis by two economists.

Nicholas Burger of RAND and John Lynham of the University of Hawaii looked at the results for roughly 50 people who placed bets with William Hill, a company that does a big business taking bets on sports. The weight-loss bets are a small business that the company basically runs for the publicity it generates, the authors say.

William Hill negotiates the terms of each bet with would-be dieters individually. They usually have long odds; the dieters typically stand to win some multiple of the amount they bet.

And they require a lot of weight loss in a relatively short period of time: The average bettor weighed 263 pounds at the outset, and had to get down to 180 in about eight months to win the bet. (There's a lot of variation, but this gives you the general idea.)

In 80 percent of the cases, the dieters lost the bet, Burger and Lynham found.

These cases are exceptional; it's tough to lose that much weight, that fast. But when I spoke with Burger on the phone this morning, he pointed out that other studies have also shown that financial incentives often fail to help people lose weight.

Economists have looked at programs where people get paid to lose weight. They've tried having dieters put up their own money, which they only get back if they meet certain weight targets. As this paper noted, neither effort worked particularly well.

Part of the problem is that the financial incentives set up for weight loss tend to be long-term, while the temptations that foil dieters are immediate.

"When you look at a doughnut, it looks amazing right now," Burger said.

In general, we tend to underestimate the benefits of things we'll get in the future versus the benefits of things we can have right now. So we eat the doughnut, even if it means we lose out on a long-term financial benefit.

This is the same problem that dieters face even when no money is on the line, Burger said. The benefits of weight loss accrue slowly, and in the long term, while the benefits of the doughnut accrue all at once, and right now.

So maybe some economist needs to figure out a way for a dieter to get paid a few bucks every time he decides not to eat a doughnut.

For more:

  • Two Yale professors created stickK, a Web site that lets people create financial incentives to encourage weight loss and other life changes. Here's an NPR story about the site.
  • Marginal Revolution has been chronicling one high-stakes, two-way weight-loss bet.
  • Obesity is getting more expensive.