MyFitnessPal is a popular smartphone app that helps people lose weight by tracking what they eat. It works a lot better when people share their food diaries with friends.
MyFitnessPal users who share their daily calorie counts with friends lose two times the weight, on average, of those who don’t share.
Users who share their food diaries with 10 or more friends lose four times as much weight as the average — an average of 22.75 pounds during the total time they spend using the app.
That’s according to a new analysis of user data as well as user surveys by the app maker. It seems to align with academic research about behavior spreading between social groups like a contagion, according MyFitnessPal VP Tara-Nicholle Nelson.
MyFitnessPal doesn’t have social features built in by default, but it encourages people to connect to friends via Facebook and email contacts. Starting today, the company’s apps — which are available for Android, iOS, BlackBerry and Windows — will also start counting steps so people can more easily measure their activity levels. (Update: Actually, only MyFitnessPal for iPhone 5s will count steps.)
MyFitnessPal CEO Mike Lee says the social workout research comes from “the biggest-ever longitudinal study of human health behaviors in history” — a.k.a. MyFitnessPal usage. “There are 60 million Americans trying to lose weight, and we have over 50 million registered users,” he said. “That’s a very significant portion.”
But it’s perhaps not quite as big as the company makes it sound, because 50 million users is the total number that has ever registered for MyFitnessPal — not the count of those who continue to use the product to track both food intake and weigh-ins.
This article originally appeared on Recode.net.