(ShareCast News) - Fitness tracking devices from the likes of Fitbit, Fitbug and Cloudtag may not actually provide any health benefits, according to new research from the US.A two-year study by the University of Pittsburgh took into account evidence from 470 overweight people between 18 and 35 and found that using such an electronic device does not improve a person's chances of losing weight.The results were published in the Journal of the American Medical Association, and showed that those subjects who wore fitness trackers lost 3.5kg during the period on average, compared to 5.9kg for those that monitored themselves.Sales in such wearable devices such as watches and smartphones have grown massively in recent years, with around 10m supposed to be in circulation by the end of the year.Scientists from the university said in the journal that they were surprised by the results."When we started this we hypothesised that we were going to see the opposite of what we found," John Jakicic from the University of Pittsburgh said. "We thought, 'Hey, if we add this technology to an already good programme, it will do even better.'"In a separate press release, Jakicic said that the trackers "may give people somewhat of a false sense of security" surrounding their weight.