I'm not sure if DietBet is actually a new program, if it's just recently become popular either in general or in my circles specifically, or if (surely not!) I just haven't really been paying attention. Regardless, I've been hearing a lot about it lately. I actually don't know the details of the program exactly, but my understanding is you join a group by placing a bet of a certain amount ($$$) that you will lose 4% of your body weight in four weeks. At the end, if you haven't lost the weight, you forfeit your bet, and those who did lose the weight split the pot (after DietBet takes its cut, I'm sure).
On the one hand, I dig it. Sad as it may be, money is often a bigger motivator than health, because the consequences or rewards are concrete and immediate. There are numerous websites out there operating on this principle in one way or another (and I'll take a moment to shout out to my friends at Beeminder, who really put a lot of thought into how they use that motivation). So here's a way to help people force their own hands in making positive changes in their lives. And that's good!
On the other hand, 4% is a lot. If a patient lost that much weight without intending to, that might be a red flag for a dietitian (5% or greater weight loss in one month is considered "severe"). For a significant portion of people who truly need to lose weight, it means exceeding the recommended 2lbs/wk weight loss. It requires pretty significant calorie restriction. I'd have to create a deficit of over 750 calories every day for four weeks to be successful. That's pretty intense! And at the end of it, you know what I bet I'd do with my hard won (lost?) money?
I'd buy a really big cookie.
Which leads me to my... er... other hand. The kinds of restrictions that lead to this sort of speedy weight loss aren't sustainable. They're so restrictive, they feel like a punishment. They make you crave the foods you're shunning, they make you crave reward. The habits you have to develop to lose weight this quickly are not the habits you can carry with you throughout your life to help maintain a healthy weight.
So when I see friends or acquaintances or other blog authors proclaiming they've won their latest DietBet, all I can think to say is... nothing. I don't want to be the Negative Nancy poo-pooing on them taking a step in the right direction. But I also don't want to offer my heartfelt congratulations for taking that step in what I consider to be an irresponsible way.