For those looking to lose weight, a two-year study suggests that wearing a fitness tracker helps. What surprised researchers, however, is that not wearing one seems to help even more, reports Ars Technica. The study in JAMA, perhaps the most comprehensive to date on the subject, followed nearly 500 overweight people ages 18 to 35 over 24 months. For the first six months, all participants used the same strict diet and exercise regimen, and all lost weight. For the last 18 months, half the group got a fitness tracker and half went tech-free. The bottom line: Those who wore no monitor ended up an average of 13 pounds lighter than when they began, while those who wore the device ended up 8 pounds lighter, reports the New York Times.
“We were definitely surprised,” says Dr. John Jakicic of the University of Pittsburgh. So what's going on? Scientists aren't sure and hope to do follow-up studies to find out, but they theorize that some people wearing the trackers might get discouraged when they fail to hit daily goals and give up. One caveat: The device in the study was a FitCore armband, which isn't quite as advanced as devices on the market today, typically worn around the wrists. "Instead of using heart rate to estimate activity like some devices do, it measured the heat generated by exercise," explains NPR. A spokesperson for FitBit says its devices go far beyond such data collection to provide "insights" and "motivation," per the Guardian. (Read more fitness stories.)