Fitness Tracker Doesn't Help You Lose Weight, Study Finds

Fitness trackers, wearable devices that provide information about heart rate, steps walked, or calories burned, have been widely heralded as the technological solution to national rates of obesity and lack of exercise. By providing immediate and accurate information about users' workouts and physical exertion, these trackers both encourage more activity and prevent people from deceiving themselves about their exercise habits, so they should lead to an increase in overall fitness.

At least, that was the hypothesis. New evidence suggests otherwise.

Published Tuesday in the Journal of the American Medical Association, a study from the University of Pittsburgh and led by researcher John Jakicic found that young adult subjects who received weight loss counseling as well as a fitness tracker actually lost less weight on average than those who just received the counseling.

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“The findings of our study are important because effective long-term treatments are needed to address America’s obesity epidemic,” said Jakicic in a press release. “We’ve found that questions remain regarding the effectiveness of wearable devices and how to best use them to modify physical activity and diet behaviors in adults seeking weight loss.”

How exactly did the researchers conduct the study?

Over the course of two years, they monitored 471 subjects enrolled in a weight loss study. For the first six months, subjects were put on a low-calorie diet, were told to exercise more and attended group counseling. After six months, about half were given a fitness tracker to monitor their activity with a corresponding website, and the other half or so were just instructed to self-report their activity online.

Participants were weighed over the course of the study, and at the end of 24 months, the group without the fitness trackers lost more weight than those who used fitness trackers.

"These devices should not be relied upon as tools for weight management in place of effective behavioral counseling for physical activity and diet," Jakicic concluded.

On average, the people who wore fitness trackers lost 7.7 pounds, while those who didn't lost 13 pounds.

The authors note that the difference between the groups is hard to explain. Aside from the difference in weight loss, there were no other significant differences between the two groups, including in measured diet changes and overall activity level. However, because some of these measures relied on self-reporting, there may be differences that the researchers did not capture.

One limitation of the study was that only 75 percent of participants who started the program finished it, which could bias the results. However, about a third of those who dropped out were excluded because they became pregnant or left the area, and these factors are unlikely to introduce bias.

The study's fitness tracker was worn on the upper arm, rather than on the wrist, as is also a popular option. The authors doubt that different placement of the fitness tracker would lead to the substantial differences in results, especially since research has found some wrist trackers to be inaccurate, but this is a potentially confounding factor when generalizing the study's findings.

Another study from 2011 found completely opposite results from the new paper. Those researchers found that using weight loss counseling paired with a fitness tracker was actually the optimal strategy for losing weight. That paper, however, was somewhat more limited than the most recent study, with about half as many subjects and only a 9-month time frame.

Both studies were dominated by a majority of women; 77 percent of subjects in the recent study were women, compared to 81 percent of the 2011 study participants (who were also somewhat older on average). It's possible the results of fitness trackers on weight loss would be different if the studies included more men.

A spokesperson for Fitbit, a popular producer a fitness-tracking products, contacted Patch after an initial version of this article was published to contest the idea that the study's findings apply broadly.

"The University of Pittsburgh study published in JAMA did not use Fitbit devices or the Fitbit app, so we cannot speak to their specific findings," Patch was told. "As the leader in the wearables category, we are confident in the positive results users have seen from the Fitbit platform."

"It would be unfair to draw conclusions about the benefits of wearables or trackers generally based on the limited way they were used in this study," the spokesperson added.

Photo credit: Peter van der Sluijs via Flickr