If you want to drop a few kilograms, perhaps think twice about dropping a few hundred dollars on a Fitbit.
A new study out of the US suggests they're an obstacle to losing weight, rather than a help.
Hundreds of dieters were equipped with wearable devices that monitor physical activity and calorie intakes, and put on diets and exercise regimes. Hundreds of others also dieted and exercised, but had to log their progress without the benefit of a Fitbit-like device.
At the end of the trial those with the devices lost an average of 3.5kg, while those doing it old-school burned off 5.9kg.
"Devices that monitor and provide feedback on physical activity may not offer an advantage over standard behavioural weight loss approaches," the University of Pittsburgh study concluded.
Both groups showed improved fitness and lower body fat percentage.
Oddly however, both groups lost more weight in the first six months than they did over the course of the two-year trial, putting some of it back on over the remaining 18 months.
"Challenges remain to sustaining weight loss long-term," the study notes.
The findings were published on Wednesday in The Journal of the American Medical Association.