Okay, I admit it. I downloaded MyFitnessPal ages ago with the intention of keeping track of what I ate.
I made the effort for a few weeks — or was it days? — then gave up, even though I know that research shows that keeping a food diary is key to losing weight. In fact, a 2008 study by the Kaiser Permanente Center for Health Research found that doing so can double a person's weight loss.
What if I put my money where my mouth is? The app formerly known as GymPact, which paid users when they exercised and docked them when they didn't, has relaunched as plain old Pact, with freshly designed apps for iPhone and Android, and two new options for encouraging healthy habits.
Now, in addition to earning/losing money for exercise, users can reward or punish themselves for eating their vegetables or — drumroll — simply keeping track of their calories through an interface with MyFitnessPal. (And, no, you don't get punished if you go over your caloric goal. All you have to do is track your intake.)
Here's how it works: First, set a weekly goal, such as logging your meals four days a week. Then, decide how much you are willing to pay other users, via a credit card charge, if you don't make that goal (a minimum of $5).
Keep to your goal, and you get a small reward — in this scenario, 80 cents a week — from the pool of money generated by payments from those who didn't keep their pacts. Once you have earned $10 in rewards, you can withdraw the money via Paypal.
Want to eat more veggies? Take a photo of each one you consume and send it in (the Pact community will vote on whether it counts; once a photo has been rejected it cannot be disputed, which may be unsettling).
Want to exercise? Log in at your gym or sync the runs/steps tracked on apps such as RunKeeper or devices such as Fitbit. All workouts, runs and bike rides must be at least 30 minutes; or you can log 10,000 steps a day.
GymPact was founded in 2012 by two Harvard grads who decided to implement the behavioral economics one of them had learned about in class. It claims a success rate of 92 percent, because apparently nothing motivates people like the prospect of losing money (it seems to be working with me).