Most people know they shouldn't eat that double cheeseburger. But Jack Lesko, 29, gets real-time reminders from virtual friends. "They're like, 'Hey, man, what's going on?' " he says of peers on the Eatery, a new photo-sharing smart-phone app that has users award one another points for eating healthy or withhold them if they're not. "It's fun," Lesko says, and also effective: that social accountability has helped him drop 60 lb. (27 kg)--and counting.
Games are the future of health care--or one version of it. At least 124 million people use smart phones to log exercises, track blood-glucose levels and even...