FitBit Trackers May Overestimate Calories Burned

Researchers say some trackers overestimating burned calories by 50%!

January 30, 2019



I was so excited when the hubby bought me my FitBit! I wore it daily because I wanted to keep track of my activity. Domino, our human google afternoon guy, argued with me and said "those things are way you take that many steps on an average day." Thanks a lot Domino aka "Debbie Downer." Well, sigh, apparently he was correct. Boy, I'll never hear the end of it now.

So while my co worker argued the steps were incorrect that leads obviously to how many calories you are burning as well. Researchers at Aberystwyth University measured the amount of oxygen a volunteer used during ten-minute walking and running sessions on a treadmill, comparing the data to information gathered by trackers. They found the FitBit Charge 2 was fairly accurate in estimating the calories burned while running, underestimating by only 4%. However, the devices underestimated the calories burned during walking by more than 50%. Other less expensive devices, such as the Letscom HR and the Letsfit, were more accurate during the walking test, overestimating calorie burn by 15% and 2% respectively. But they underestimated the total during running by 33% and 40%.

Researcher Dr. Thatcher said, “If you want to know the exact number of calories that you are burning during an exercise session then it doesn’t matter which device you use, you have to interpret the data with some caution.”

Oh and you'll love what FitBit's reponse was to these findings. A spokesperson for FitBit said, “We do not claim to be scientifically accurate at the number of calories being burned.”

The other two brands said they could offer only estimates based on data inputted by users such as height and length of stride, but that their trackers are not scientific devices.

Wow. Really? So I basically own a watch? Sigh. ~grace