Many people trying to reduce weight wear a fitness tracker, but recent research has thrown up a surprise. People who count their steps generally lose less weight than those who exercise “tech-free”. The US study followed 500 young overweight adults over two years, half of whom wore the smart wristbands. The study showed that those wearing wristbands lost an average of 3.5kg while those without lost 5.9kg. There are many theories as to why this happened. One is that wearers rely too much on their devices and do not think as much about other factors, such as diet. Another is that wristbands are impersonal and do not advise or encourage the wearer.