CALORIE COUNTERS CAN’T COUNT.
Calorie counting is a useful way to lose weight, but a new study suggests a fitness tracker could sabotage your efforts, reports Travis M. Andrews. THE CLAIMS
Fitness tracking devices are overwhelmingly popular. For instance, since its inception, the leading brand, Fitbit, has sold at least 30 million of them. The company promises on its website that the devices “track steps, distance, calories burned, floors climbed, active minutes & hourly activity.” Others, such as PulseOn, Apple Watch, Basis Peak, Samsung Gear S2 and Microsoft Band, promise the same.
THE STUDY
A team of Stanford researchers, however, recently called foul after testing these trackers. The scientists said in a paper published Wednesday in the Journal of Personalized Medicine that though the devices purport to help users track their calories — daily energy expenditure — the number is often markedly incorrect. The least accurate, PulseOn, was off by an average of 93 per cent. The most accurate device, Fitbit Surge, was off by an average of 27 per cent, the Guardian reported. “People are basing life decisions on the data provided by these devices,” Euan Ashley, a professor of cardiovascular medicine at Stanford and co-author of the study, said in a news release.
THE CONSEQUENCES
Let’s say, as a hypothetical, some users check their device at the end of a long day and discover to their delight they burned 1,000 calories when they actually only burned 730. They might have an extra dessert or glass of wine since they think they’ve met their goal. “It’s just human nature,” Tim Church, professor of preventative medicine at Pennington Biomedical Research Center at Louisiana State University who wasn’t involved in the study, told NPR. “People are checking these inaccurate counts and they think they’ve earned a muffin or earned some ice cream and they’re sabotaging their weight-loss program.”
THE KEY
One of the key issues, hypothesized Anna Shcherbina, a Stanford graduate student and study co-author, was the difference in users’ body compositions. “It’s very hard to train an algorithm that would be accurate across a wide variety of people because energy expenditure is variable based on someone’s fitness level, height and weight, etc.,” Shcherbina said.
THE DEFENCE
In a statement to NPR, PulseOn said the extremely high level of inaccuracy may “suggest that the authors may not have properly set all the user parameters on the device.” The consequences of such large margins of error could, of course, be significant.