Too Much TV, Video and Computer Making Teens Fatter
Author: University of Montreal
Published: 20 Sep 2010 - Updated: 29 Jun 2026
Publication Details: Peer-Reviewed | Research, Study, Analysis
Table of Contents:
Synopsis - Definition - Introduction - Main - Insights, Updates - Related Publications
Synopsis: This research, a peer-reviewed five-year study from the University of Montreal and the Sainte-Justine Hospital Research Center published in the American Journal of Epidemiology, followed 744 students from 10 Montreal high schools who reported their screen time and physical activity 20 times over the course of the investigation while researchers repeatedly measured their height, weight, and body fat. Led by Professor Tracie A. Barnett, the study identified four distinct patterns of screen use - increasing, decreasing, consistently high, and consistently low - and found that teens whose screen time rose or stayed high saw the greatest increases in percent body fat, while those who reduced their use ended up with the most favorable profiles. Because it tracked the same adolescents repeatedly across five years rather than at a single point, it offers a credible, evidence-based reference for parents, educators, and public health planners concerned with youth weight and sedentary behavior.*
At a Glance
- 1 - Even teens in the consistently low group averaged more than two hours of screen time a day.
- 2 - About 30 percent of adolescents showed atypical patterns that rose, fell, or stayed high, and these had the greatest effect on weight gain.
- 3 - Researchers recommend reaching children before high school, since most already have firmly established viewing habits by the time it begins.
- Topic Definition: Teen Screen Time and Body Fat
Teen screen time and body fat refers to the study of how the hours adolescents spend watching television, playing video games, and using computers relate to changes in their body composition, particularly the percentage of fat they carry. Researchers in this area examine not only the total amount of screen use but the pattern it follows over time - whether it rises, falls, or holds steady through the teenage years - because these trajectories appear to influence weight differently. The concern is largely that sedentary screen use displaces physical activity and other healthful pursuits, and most guidance, including recommendations to limit recreational screen use to about two hours a day, aims to curb excessive viewing before lasting habits take hold.
Introduction
Teen Screen Time and Rising Body Fat - 5-Year Study
A five-year study from the University of Montreal and the Sainte-Justine Hospital Research Center, published in the American Journal of Epidemiology, has found teenagers have four different patterns of screen use: increases, decreases, consistently high and consistently low users.
Even teens from the consistently low group exceeded two hours per day of screen time on average, yet organizations such as the American Academy of Pediatrics and the Canadian Paediatric Society recommend limiting screen use to two hours per day. Increases and consistently high screen users had the greatest increases in percent body fat, while decreases had the lowest gains in percent body fat
Main Content
While the majority of adolescents in the study maintained a typical ''flat'' pattern of 25 to 30 hours of screen time per week, close to 30 percent of adolescents had screen time patterns that increased, decreased or remained high over time. The scientists found that these atypical' patterns had the greatest impact on weight gain.
"There is some concern that adolescents' television, video and computer use is filling much of their discretionary time" says lead author Tracie A. Barnett, a professor at the Universite de Montreal's Department of Social and Preventive Medicine and a scientist at the Sainte-Justine Hospital Research Center. "Our findings show that youth are at greater risk of increased body fat if screen use increases through high school; one possible reason is that teens who increase their screen time are simultaneously reducing involvement in and opportunities for more active pursuits."
Similarly, teens that had initially high levels of screen use but dropped their screen use over time ended up with the most favorable body fat profiles.
Dr. Barnett and her team evaluated 744 participants, as of grade 7, from 10 Montreal high schools. Teens reported screen time and their level of physical activity four times per year or a total of 20 times during the five-year study. The research team also measured height, weight and body fat of participants several times over the course of the investigation.
"The high levels of screen time observed in our study underscore the need for public health strategies to reduce overall screen time among youth. Encouraging less screen time, and some form of monitoring to prevent excessive increases in screen time through high school, would be beneficial to teenagers. Since most already have firmly established viewing habits at the start of high school, these strategies also need to target kids before they even begin high school," says Dr. Barnett.
Partners in research: The study was funded by the Canadian Cancer Society, the Fonds de la Recherche en Sante du Quebec and the Canadian Institutes of Health Research.
The study, "Teens and Screens: The Influence of Screen Time on Adiposity in Adolescents," published in the American Journal of Epidemiology, was authored by Tracie A. Barnett, Jennifer O'Loughlin, Igor Karp and Andraea Van Hulst of the University of Montreal; Marie Lambert of the Sainte-Justine Hospital Research Center; Catherine M. Sabiston of McGill University and Mathieu Belanger of the Center de Formation Medicale du Nouveau-Brunswick.
Related Information
- Link Between Child TV Time and Metabolic Syndrome
- Use of Electronic Devices to Calm Kids
- When Children Are Allowed TV and Games in Bedroom
- Gaming Disorder Disability: Video Game Addiction (VGA)
- Screen Time Linked to Psychological Problems in Children
- Why Babies Under Two Should Have No Screen Time at All: UK researchers warn that screen time for children under two carries long-term health risks and offers few real benefits during early development.
- Link Between Excessive Screen Time and Teen Suicide Risk
Insights, Analysis, and Developments
Editorial Note: The quiet lesson of this study is that the direction of a habit may matter as much as its size - it was not simply the heaviest viewers who fared worst, but those whose screen time climbed through their teenage years, while the adolescents who managed to pull back ended up healthier than their starting habits would have predicted. That offers a genuinely hopeful note in a field often dominated by alarm, suggesting the trajectory is not fixed, though Professor Barnett's reminder that viewing patterns are largely set before high school makes a strong case for acting early rather than waiting for the numbers to drift upward.*Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by University of Montreal and published on 20 Sep 2010, this content may have been edited for style, clarity, or brevity.
* Editorial additions by Ian C. Langtree.