Depending on the site, you can sign up with a group of friends or as an individual. If you skip the gym, miss your goals, or don’t lose the weight you promised, you pay a predetermined fine. Most sites donate the profits to charity, but some shell it out to users who have met their goals.
Whether this approach works for long-term weight loss is still up for debate. A recent 32-week study from Carnegie Mellon University found that participants with a financial incentive did in fact lose more weight than a control group. But after an eight-week weight loss maintenance phase, those who had money at stake were unable to maintain their new weights, so there was no long-term difference between the incentivized dieters and the control group.
But if you’re feeling confident in your ability to lose weight and make a few bucks, or if you need an extra kick to stay on track, check out this list of buzzy new sites that let you wager on weight loss.
Get Cash for Going to the GymCreated by two recent Harvard grads, Gym Pact (http://www.gym-pact.com/) is an iPhone app that forces users to hit the gym or pay up — $5 per missed workout. On the flip side, every week you hit your exercise goals, you’re rewarded with real cash.
How it works: There’s no sign-up fee, but each week you’re required to commit to at least one workout (worth $5). If you want to push yourself harder, you can add more gym sessions to your weekly rotation. Once your goal is set, check in on the app every time you hit the gym. At the end of the week, the money collected from non-exercisers is divided up among people who reached their goals. And just like you did in middle school, if you miss the gym due to illness, your doctor can send in a note to Gym Pact to score you a refund.
Win Prizes for Weight LossLose 10 percent of your body weight over six months and automatically win $100. That’s the promise behind Healthy Wage (http://www.healthywage.com/ ) a site that’s so far shelled out more than $430,000 to dieters who’ve lost more than 860,000 pounds.
How it works: Join one of two ongoing challenges as an individual to compete only against yourself and shed weight or lower your BMI, or enter the Matchup Challenge as part of a five-person team and become eligible to win the site’s $10,000 first prize. There’s a participation fee for each challenge, which in turn becomes prize money for the winners. To give you an idea what you’re up against, the most recent five-person team to win the Matchup Challenge lost 266 pounds over 14 weeks and walked away with $10,000.
Try Free Weight Loss WagersIf you’re not ready to lose real money over that second slice of pizza, try Fat Bet (http://fatbet.net/home.aspx), a free site that lets you create your own weight loss group challenge with friends. You’re encouraged to make wagers that are fun, embarrassing, or include some kind of service or challenge that the loser has to perform — think running naked, singing karaoke, or washing the winners’ cars. If you win, you get nothing but bragging rights and a slimmer bod.
How it works: Gather a group of friends and either set a pound or percentage weight-loss goal. Everyone in the challenge uses his or her own scale to weigh in daily, and then enters weights online using the honor system. If everyone loses the weight-loss wager, everyone pays.
Meet Any Health GoalFounded by Yale University professor Dean Karlan, PhD, as an “online commitment store,” StickK (http://www.stickk.com/ ) is designed to help you stick with your goals, whether you want to exercise more, quit smoking, sleep more, or something else entirely.
How it works: Because your goals can be about anything, you set your own and define the stakes on your own — money is optional. Next, you invite someone you know and trust to be your goal referee, and add friends on the site to act as your virtual cheerleaders. In a rather unusual offering, StickK also allows users to elect to send failed goal money to a charitable cause they abhor. For example, if an anti-gun advocate misses his or her workout goals for the week, the fees they incur go straight to a gun-rights organization. This might seem like a harsh incentive to stick to your goal, but Karlan’s behavioral economics research indicates it works.
Play a Weight Loss GameFarmville addicts, look no further than Diet Bet (http://www.dietbet.com/). This free-to-join, four-week game with friends helps you lose weight — go for either 8 pounds or 4 percent of your beginning weight — with a monetary bet (you pick the level each player puts in the pot) and fun bonus stakes, such as dinner on the loser.
How it works: Visit the site to set the amount of money each dieter has to throw in and whether you’re judging based on pounds or percentage of weight loss. Invite friends to join you on Facebook and Twitter, and you’re off. After four weeks, whoever loses the most weight takes home the whole pot.
Make or Break Any HabitIt takes 21 days to make or break a habit — good or bad — say the founders of 21Habit (http://21habit.com/) a new site for making or breaking goals. One of the simplest sites on the list, 21Habit allows you to simply input your goal, select “committed” or “free” mode, and go.
How it works: Set your goal, and if you choose the committed mode, bet $21 up front. You can also try the site for free without wagering anything. Every day, check into the site to record how you’re progressing toward your goal. Each day you succeed, you get $1 of your original 21 back. Each day you fail, you automatically forfeit $1, which the site donates to charity. You can also try the site for free without wagering anything.
Collect Real Rewards for Healthy HabitsWhether it’s time to lose your baby weight before you go on vacation or quit smoking because your doctor says so, Health Rally (http://www.healthrally.com/) can help. Founded by neuroscience researcher Zack Lynch and software guru Peter Kaminski, the site allows your family and friends to pledge money to reward you for reaching your goal. (Think $150 pledged by your friends for new running shoes after you complete your first 5K.)
How it works: When you visit the site, choose the person you want to motivate (yourself or a friend) and create a custom profile explaining the health goal, and the reward you want. Next, share your goal or rally with your social networks, and sit back and wait for the support to start flowing in.