HEALTH

Fitness trackers may not help people keep weight off long-term

Fitness trackers are marketed as a way to increase your activity, but it turns out they may not help users keep weight off in the long term. A new study finds that among overweight and obese adults who have lost weight, those using a fitness tracker gained back more weight than those without.

Why it matters:

The makers of fitness trackers tout the gadgets as weight-loss aids — for instance, Fitbit has partnerships with Weight Watchers and Medifast to add the wristbands to their diet regimens. But do they work? John Jakicic at the University of Pittsburgh has done previous research showing that wearable fitness devices could be just as beneficial as in-person fitness counseling — but they were all short-term studies of around six months. He wanted to know: If you added wearable technology after people lose weight initially, could it help them continue their progress?

The nitty gritty:

Jakicic and colleagues recruited 470 overweight or obese adults for an exercise and dieting program. For the first six months, they had group sessions on calorie restriction and physical activity; the participants lost a significant amount of weight. Then Jakicic and his team reduced face-to-face meetings (replacing them with phone counseling and self-reporting via the web) and gave about half the group received wearable devices.

The armbands, made by BodyMedia, recorded steps, minutes of activity, and total energy expenditure. The wearables group also had access to a website where they could upload their calorie intake and compare it to calorie expenditure. The group without a device was still encouraged to log their diet and exercise, but it was done in a “cruder” way, said Jakicic.

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At the end of 24 months, the group with the armbands had lost, on average, 7.7 pounds. In comparison, those without lost an average of 13 pounds, about 5.3 pounds more. The study was published Tuesday in the Journal of the American Medical Association.

But keep in mind:

The wearables were introduced six months into the program, a tough time for weight loss, said Holly Lofton, the director of the medical weight management program at NYU Langone Medical Center. Lofton, who was not involved in the study, said that six months in, she often sees people hit a plateau that can be difficult to overcome without increasing physical activity. Also, most of her patients who are successful with fitness devices use them from the very beginning of their weight-loss efforts.

What they’re saying:

Jakicic’s team is continuing to look at the data to understand why fitness trackers had this effect. It’s possible, he said, that the devices distract from the total picture of weight loss by focusing solely on steps and activity. Or, participants may be semiconsciously undoing their efforts. “They say, ‘Hey, I hit my activity goal today, I can go have a hamburger,’” Jackicic said.

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In an opposite scenario, your Fitbit could be a daily reminder that you’re not reaching your goals. “These devices are really built for people who like activity and are motivated by this information,” Jakicic said. “For people that don’t like activity, they may look at this and go, ‘Oh, the heck with this, I’m not going to make it anyway, so why bother today.’”

In all his hypotheses, Jakicic says that wearables should be more focused on behavioral or psychological factors, rather than just information. Lofton agreed, saying that there’s a difference between using a wearable device and relying on a wearable device, and that she still recommends them to all her patients.

The bottom line:

Activity trackers, while helpful for some people to meet their fitness goals, don’t work in all scenarios, and researchers are still trying to figure out who they do work for and what kind of feedback motivates good habits.