Wearable fitness devices offer no 'advantage' over standard weight-loss approaches
But 1 of the researchers in JAMA study says the devices 'made a difference' for some of the subjects
Young, overweight or obese adults who added wearable fitness trackers to their weight-loss plans failed to shed more pounds, U.S. researchers studying more than 470 people have found.
Wearable devices such as Fitbit and Jawbone UP are marketed to monitor physical activity, as well as other efforts including monitoring diets; though those devices weren't the ones used in the study.
To determine whether wearables contribute to weight loss over the long term, researchers had 471 individuals aged 18 to 35 participate in a six-month clinical trial of a low-calorie diet, prescribed increases in physical activity and group counselling.
The subjects were then randomly assigned to another six months of telephone counselling, text message reminders in addition to donning a wearable device to self-monitor their diet and physical activity, or access to a website as a control.
Men and women in the study had a body mass index (BMI) of 25 to less than 40. The index is based on height and weight, with a score over 30 considered obese.
After two years, weight loss was about five pounds less among those in the wearable devices group compared with subjects in the standard group (using the website), John Jakicic of the University of Pittsburgh and his co-authors said in Tuesday's issue of JAMA (Journal of the American Medical Association.)
Weight loss was also greater in the standard group versus the wearable group at 12 months and 18 months.
"Devices that monitor and provide feedback on physical activity may not offer an advantage over standard behavioural weight-loss approaches," the researchers wrote.
Both groups had significant improvements in body composition, fitness, physical activity and diet, with no significant difference between groups, they said.
In total, 75 per cent of participants completed the study.
Estimated average weights for the group wearing trackers were 212 pounds at study entry and 205 pounds at 24 months, resulting in an average weight loss of about 7.7 pounds.
In comparison, those in the website group started out at 210 pounds when the study began and weighed in at 197 pounds at 24 months, for an average loss of 13 pounds.
Still, Jakicic said in an email: "We should not send the message that these wearable technologies do not help with weight loss — there were some in our study for whom it made a difference.
"There is so much more that we need to learn about how these devices lead to behaviour change."
The reason for the difference in weight loss between the two groups warrants further investigation, the study says.
Keeping weight off is notoriously difficult. The researchers called their findings important because of the lack of data to support effective weight-loss approaches in young adults, who have a high prevalence of overweight and obesity.
Weight loss also isn't the only end point that might change with a wearable device, said Gary Miller of Wake Forest University Health and Exercise Department in Winston-Salem, N.C. He wasn't involved in the study.
"The comparison group is really not the average person out there," Miller told Reuters Health. "There are so many factors that affect weight loss, it's difficult to say that these devices aren't worthwhile or aren't necessary for people just based on weight loss."
The results can't be applied to other ages.
Participants in the study were provided with a BodyMedia Fit Core, a wearable activity tracker worn on the upper arm. The Fit Core tracks steps, hours slept and calories burned and costs about $100 US.
The study was funded by the U.S. National Institutes of Health and the U.S. National Heart, Lung, and Blood Institute.
Some of the study's authors received honoraria for serving on the scientific advisory board for Weight Watchers International or have received a grant from a wearable maker.
With files from Reuters