A recent study of 470 overweight or obese people sought to measure the effect of fitness trackers on weight loss.
During the first six months of the study, all of the participants were put on a low calorie diet and instructed to increase their physical activity. That seemed to work out pretty well, and the great majority of the participants slimmed down.
However, for the subsequent 18 months, half of the participants were equipped with fitness trackers that recorded the steps they took per day, while the other half continued to simply report their food intake and physical activity in a journal.
At the end of the two-year period, those with trackers actually lost less weight than the others. They shed an average of 13 pounds, compared to only 7.7 pounds for those with the trackers.
It’s not a particularly surprising phenomenon for those who are familiar with weight loss strategies. Research has shown that an emphasis on exercise often simply leads people to eat more. Although the people in this experiment were encouraged to eat less, they likely felt entitled to splurge as long as their tracker told them they had exceeded their daily step goal.
"People would say, 'Oh, I exercised a lot today, now I can eat more.' And they might eat more than they otherwise would have,” John Jakicic, a University of Pittsburgh researcher who authored the study, told NPR.
A number of nutrition advocates have voiced dismay in recent years at the focus on physical fitness when addressing obesity. Indeed, food industry giants, including companies such as Coca Cola, have invested greatly in public relations and lobbying efforts to promote ideas and policies that stress exercise over nutrition. A 2014 documentary produced by Katie Couric, Fed Up, argued that Michelle Obama’s anti-obesity initiative changed course to focus on exercise as a result of pressure from the food industry.
Wearable fitness technology has also been the subject of scrutiny over its accuracy in measuring physical activity. In May, a study found that Fitbit, one of the major manufacturers of fitness trackers, were often wildly off. The trackers miscalculated users’ heart rate by 20 beats per minute on average.
Fitbit, one of the leading makers of fitness trackers, downplayed the results of the study, pointing out that the data was collected in 2010-12. Wearable devices have improved dramatically since then, the company said in a statement provided to BenefitsPRO.
"We would strongly caution against any conclusion that these findings apply to the wearable technology category as a whole," the company said, pointing out that it was not the maker of the unidentified devices used in the study.