Study results: Fitness trackers don’t count calories

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Workout enthusiasts and athletes might wear a fitness tracker to help them to keep on course with their healthful lifestyle. How accurate are these devices in doing that? Dr. Mikael Mattsson, who is a visiting assistant professor at Ashley Lab, School of Medicine, at Stanford University, says people shouldn’t base their caloric intake on the data that wrist-worn fitness trackers provide about “calories burned.” You should take those calculations with a grain of salt. 

A study that was perform-ed by Mattsson and his colleagues at Stanford, which was published May 2017 in
Journal of Personalized Medicine, evaluated seven “wristband activity devices” that included the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn and Samsung Gear S2. They found that none of them accurately measures energy expenditure (calories burned). 

Mark Gorelick of Mio Global says “[W]e agree that more-accurate calorie estimation is important for the industry as a whole, since most individuals are monitoring calorie deficits for weight loss.”

Mattsson points out that the inaccuracies that he and his team saw lay in the devices’ software. Noting that the software in the devices was updated after their testing was carried out, Mattson says the team is conducting another study. He expects that the devices’ accuracy in measuring calories burned will improve, but “it will take some time before they are good enough for all individuals.”

The researchers at Stanford hope that Food and Drug Administration eventually will test fitness trackers.