A new study into the effects of fitness trackers has cast doubt over whether they can help users lose weight.
The experiment run by John Jakicic of the University of Pittsburgh organised two Weight Watchers groups of around 470 18-35s. One group was given the standard advice of healthy eating and increased exercise, and the second the same, but armed with fitness trackers six months into the study. The control group lost an average of 13lbs over the duration of the study, while the group using fitness trackers lost just 7.7lbs.
The report has been published in the Journal of the American Medical Association, yet despite the strong findings, there's little in the way of firm conclusions about why the fitness tracker group performed so poorly.
The report concludes that it could be that the group that had steps reported felt they could eat more, given their hard work during the day. However, there could be another option: that for some of the group, being so far away from their step goal could be a demotivator.
"These are people who are already struggling, and already don't like activity," he says. "They look down and see, 'I am so far away from my goal today, I can't do it.' It could be working against them," Jakicic told Time.
There are problems with the study. Little detail is offered on the activity schedule of the group. By the very notion of using an activity tracker in the test, there should be more data on the behaviours of the subjects involved. But that qualitative information doesn't colour the conclusions.
What's more, the study used an extremely dated BodyMedia upper arm tracker. The unusual position, lack of easily accessible data and decision not to use a more aesthetic, commercially pleasing product could undermine many of the conclusions of the study.
That was echoed by a Fitbit spokesperson, who suggested that the study was undermined by not using modern fitness trackers, with better-developed reporting.
"With regard to the study, the researchers point out that a limitation of their work includes the fact that they did not use a modern wearable device such as those offered by Fitbit. The upper arm device used in the study was limited to automatic data collection only," the spokesperson said.
"Most wearables today, including those offered by Fitbit, go far beyond data collection, offering individuals real-time access to their information, insights, motivation from associated social networks, and guidance about their health. We would strongly caution against any conclusion that these findings apply to the wearable technology category as a whole."
Not a magic bullet
However, it's a strong warning that fitness trackers aren't the magic bullet many people think they are, when it comes to weight loss and getting fit.
In our report of successful goal tracking, we concluded it was important for the metrics and data from fitness trackers to make up part of your plan.
We spoke to data science consultancy Profusion's CEO, Mike Weston, who outlined the many factors at play in successful fitness tracking:
"Wearers can be unsure about what to do with the information they've collected. This is another reason why some people do not get on with tracking in the long term," he said.
"The data can lose its value if it doesn't have any context. A wearable that can tell you how to improve your health, how to increase your stamina or decrease your lower back pain would add a whole new dimension to the user experience. By adding in complex information about how your fitness regime compares to people in the same profile can also make it easier to determine what you should be doing to stay healthy."
By just giving its subjects fitness trackers without building them into the system, Jakicic's study was perhaps always going to work out negatively for the fitness tracker. But in many ways, that's the point. Too few users use fitness bands affectively expecting the tech to be the magic bullet. The conclusions of the study show that much work is still to be done by tech companies to make their fitness tech really work for users.