Wearing a Fitbit is not making you any healthier, according to a study of 800 workers in Singapore who wore the activity-tracking devices over a year.
Even when cash incentives and charitable donations were offered to members of the study, users did not increase their activity levels enough to improve health.
Within six months, 40 per cent of participants stopped wearing the devices. This blew out to 90 per cent at 12 months.
The findings published today in the Lancet Diabetes and Endocrinology journal may disappoint scores of Australians who have invested in the devices but won't come as a surprise to many in the fitness industry.
An employee at a major gym told Fairfax Media out of 25 personal trainers he works with only one wears an activity tracking device.
Smaller trials have heralded similar results, including a Washington study last month that found people's activity levels were unchanged after they stopped using their devices.
The larger study funded by Singapore's Ministry of Health used Fitbit Zips which users wear on their waists. The device tracks steps, distance travelled, calories burned and active minutes.
Employees from 13 companies were randomly separated into four groups - those without devices, a group with just the Fitbit, a Fitbit group who got a charitable donation when they reached their goals, and a Fitbit group who received cash incentives.
Wearing the devices did not increase a person's daily steps and only increased their aerobic activity by an average 16 minutes a week, said lead author Eric Finkelstein from Duke-NUS Medical School in Singapore.
"However, we found no evidence that the device promoted weight loss or improved blood pressure or cardio respiratory fitness, either with or without financial incentives," Professor Finkelstein said.
"While there was some progress early on, once the incentives were stopped, volunteers did worse than if the incentives had never been offered, and most stopped wearing the trackers."
Fitbit released a statement in response to the survey on Tuesday, saying: "We are confident in the positive results our millions of users have seen from using Fitbit products.
"In addition to the numerous studies that demonstrate the health benefits of fitness trackers, new research from Fitbit Group Health corporate wellness customers demonstrates the positive impact of corporate wellness programs on healthcare costs," it stated.
Private health insurer Medibank Private started offering free Fitbits with new insurance policies in 2014 and has continued to reward users that meet their daily 10,000 step goal with FlyBuys points.
Qantas has also teamed up with health insurer NIB to offer frequent flyer points to customers who meet activity targets through a wellness app that syncs with wearables like the Fitbit and Apple Watch.
Leigh Benton, from country Victoria, has been wearing a Fitbit for a month and says it has helped him lose weight by tracking his calorie intake. He's also motivated to be more active but admits he doesn't reach the 10,000 steps a day goal.
"It is a driver for motivation when you look at your steps and exercise it gives you incentive to get up and do more," Mr Benton said.
But some personal trainers were sceptical, saying wearing activity trackers can be disheartening.
"The idea behind these products is great but how people actually use them in their daily lives doesn't translate into what they need to do to get the results they want," said Emma Laitala from Myofunction Personal Training Studio in Brunswick.
"There's also the competitive nature of it, people can compare with their friends how many steps they got that day and for people who aren't doing great that can be disheartening as well."
Chris Whale, a personal trainer at Virgin Active Collins Street said getting into shape was 80 per cent nutrition and 20 per cent training.
"Going out and getting a piece of technology and sitting on the couch and not doing anything with it isn't going to solve your problems," he said.
