How many pounds did you gain on your last diet? Yo-yo-ers know what I'm talking about — after you shed the initial 5, 10, or even 20 pounds, it's only a matter of time before you gain it all back, and then some. We often blame the diet for being too extreme, impractical, or not conducive to our daily lives over the long run. And that's probably the case 9 times out of 10. But maybe there's another culprit behind our dieting woes: the absence of a strong incentive. Well, today we'll talk to one economist (yes, economists diet too) who decided to put his money where his mouth is. In an op-ed for The Wall Street Journal entitled, "Dieting for Dollars," Richard McKenzie agreed to pay his friend $500 if he didn't loose 9 lbs in 10 weeks. Too easy, or easier said than done? Listen in to find out. And we'll see if he was able to keep the weight off. In the meantime, tell us, what incentives do you use to lose weight?