Fitness Trackers May Not Bring Long-term Weight Loss, JAMA Study Finds

Fitness trackers may be blockbusters for their creators—market researchers said they accounted for $1.46 billion in sales in 2015—but do they help people lose weight? A study published in JAMA this week says over the long haul, not really.

Researchers found that in a randomized controlled trial that involved overweight young adults, those who were given a fitness tracker alongside a diet and behavioral intervention had less weight loss over 2 years than the group who had the intervention without the tracker.

Study participants were 18 to 35 years old, mostly white (28.9% nonwhite), mostly women (77.2%), and had a body mass index from 25 to <40, which covers a range from just overweight to the upper limit of class 2 obesity. Of the group of 470 adults, all were put on an intensive diet and exercise program for 6 months; after that, half were given fitness trackers and half were told to self-report their diet and exercise during an extended follow-up period.

The good news is that both groups lost weight, and researchers reported overall improvements in body composition. But those in the self-reporting group lost significantly more weight: 5.9 kg, or about 13 pounds on average, compared with 3.5 kg or about 7.7 pounds for the fitness tracker group.

The device used in the study, which took place from 2010 to 2012, was worn on the upper arm—much less discreet than the Fitbits that are seen on wrists, which the authors noted. Some users have reported frustration with commercial fitness trackers, saying the calories allowed don’t match reality or they cannot keep up with the goals and get discouraged.

In the JAMA study, recommended calorie intake at baseline was 1200 calories for those who weighed 90.7 kg at the start of the study, 1500 calories for those who weighed 90.7 kg to 113.4 kg, and 1800 kg for those who weighed 113.4 kg or more. If weight loss exceeded 6% in a 4-week period or if BMI was 22 or less, calorie intake was increased. Physical activity was prescribed at 100 minutes per week, and increased at intervals until a level of 300 minutes a week was achieved.

The central challenge of any intervention, the authors stated, is sustaining weight loss over time. Study after study finds that participants initially lose weight, only to regain after the intervention ends. In this study, there were telephone contacts in months 7 to 24 and text messages twice a week to encourage participants to continue good weight loss behavior.

“Challenges remain to preventing or minimizing weight regain following initial weight loss in adults,” they wrote.

Reference

Jakicic JM, Davis KK, Rogers RJ, et al. Effect of wearable technology combined with a lifestyle intervention on long-term weight loss: the IDEA randomized clinical trial. JAMA. 2016;316(11):1161-1171. doi:10.1001/jama.2016.12858.