Over 24 months, people who used wearable activity trackers lost 2.4
kilograms (5.29 pounds) less than a group on a similar program but
using a website to track their progress.
“We should not simply tell everyone to go and buy an activity
monitor and that it will help them to lose weight,” said lead author
John M. Jakicic of the University of Pittsburgh department of health
and physical activity.
“Moreover, 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,” Jakicic told Reuters Health by
email. “There is so much more that we need to learn about how these
devices lead to behavior change.”
The researchers recruited 471 adults in Pittsburgh who were 18 to 35
years old and overweight to moderately obese. The whole group
initially met for weekly sessions to monitor weight change and talk
about diet and exercise strategies to lose weight. Over the
following year and a half, groups met monthly and each participant
also had monthly phone calls and weekly texts with counselors to
prompt engagement in weight loss behaviors.
All participants had prescribed calorie intake goals and
self-reported their intake either in diaries or on web-based
platforms. They were also prescribed 100 to 300 minutes per week of
moderate to vigorous exercise.
After six months, half of participants began monitoring their diet
and physical activity using a website and the other half 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.
After two years, people in the wearable device group had lost an
average of 3.5 kg (7.72 lb)compared to 5.9 kg (13 lb)in the group
using web-based tracking only.
Both groups had improved their body composition, fitness, physical
activity and diet, according to the report in JAMA.
This doesn’t mean that activity trackers “don’t work,” said Gary
Miller of Wake Forest University Health and Exercise Department in
Winston-Salem, North Carolina, who wasn’t involved in the study.
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“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
Weight loss also isn’t the only endpoint that might change with a
wearable device, he said.
“If (a wearable device) is what’s going to get you to exercise then
I think it’s worthwhile, but if it’s going to be a fashion statement
or something to talk about it’s not worthwhile,” he said.
“We know that monitoring activity behavior, and diet, is very
important to weight management success, so making it easier to do
that and in real-time should in theory improve success,” Jakicic
To manage your weight, you need to eat a sensible number of calories
and aim to get 30 to 60 minutes per day of moderate-to-vigorous
physical activity – similar to brisk walking in addition to as much
other activity as you can get in your daily life, he said.
“If these wearable technologies help you to do that then that is
perfect,” Jakicic said. “However, you need to use the technology in
a way that can really help you.”
SOURCE: http://bit.ly/2de1Idv JAMA, online September 20, 2016.
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