Your fitness tracker can’t do it without you

Those ubiquitous wrist units haven’t proven they can put a dent in America’s obesity problem

It’s been two weeks since you got that new Fitbit, Apple Watch or other fitness tracker for the holidays and one week since you resolved to use it to get more active, manage your weight or reach other health goals.

Congratulations — and good luck. The truth is the link between owning a fitness tracker and getting fitter isn’t as straightforward as many people might hope.

“If you put a scale in someone’s bathroom, that doesn’t mean they are going to lose weight,” says Timothy Church, professor of preventative medicine at Pennington Biomedical Research Center at Louisiana State University. “The tracker isn’t going to tie your running shoes and move your feet.”

It also won’t work if you stop wearing it or if you use all that shiny data to convince yourself you are making more progress than you really are.

Those are among the pitfalls researchers have found as they look at whether the tracking trend is likely to put a dent in the nation’s inactivity and obesity problems. Results from two of the biggest studies so far were not encouraging. In one study, reported in The Lancet

Diabetes & Endocrinology, participants given clip- on Fitbits modestly increased physical activity if they were given cash incentives. But the changes were not enough to affect weight, blood pressure or other health outcomes. And when the cash flow stopped, most people stopped using the trackers.

In a study published in JAMA, young adults in a two- year weight loss program lost less weight than others if they used an armband device to track activity, calorie burn, heart rate and other metrics.

Although it is possible results might be different with a more up- to- date tracker, study author John Jakicic is skeptical. Interviews with participants suggested one problem was the stat- keeping gave many a false sense of accomplishment, he says.

Still, many researchers believe trackers have promise. People may respond to fu- ture versions that incorporate more game- like challenges and rewards, Church says. “You’ve got to make it fun.”

People who are motivated to use trackers can be reassured that “they really do a pretty effective job of letting people quantify their lifestyle habits,” says Cedric Bryant, chief science officer of the American Council on Exercise. “But there appears to be a gap between monitoring your habits and changing them.”

Here’s the best advice for new users:

GET A BASELINE.

Start by seeing how many steps you get in a day, without adding any new activities. That “has a real educational value because most people don’t know” and may be overestimating, says Lisa Gualtieri, an assistant professor of public health and community medicine at Tufts University.

SET A PERSONAL GOAL.

The popular idea that everyone needs 10,000 steps a day is unsupported by evidence and unrealistic for many sedentary people, says Mitesh Patel, an assistant professor of medicine and health care management at the University of Pennsylvania, “The average person in the United States is starting closer to 5,000,” he says. “Doubling that on Day 1 is just too hard.”

GET SUPPORT.

“It really does take a village,” Bryant says. While your village might include fitness or health professionals, it also can include family members, friends, co- workers and others who might connect with you through the apps and websites linked to most trackers.