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Obesity

Research Summary[1]

A large body of research has demonstrated relationships between greater amounts of screen media use —television, video games, and computers — and obesity in children and adolescents. In fact, obesity is one of the most strongly proven outcomes of screen media exposure. Many studies find that children who spend more time watching or playing with screen media have greater body fatness and obesity than children who spend less time with screen media. Further, several randomized controlled trials of school curricula and family behavior change programs to reduce time spent on screens have reduced weight gain in children, demonstrating a cause-and-effect relationship. The evidence to date suggests that screen media exposure leads to obesity in children and adolescents via three main mechanisms: (1) increased eating while using screens, leading to greater calorie intake (2) seeing advertising for high-calorie, low-nutrition foods and beverages that alters children’s preferences, purchase requests and eating habits, and (3) disrupting sleep. The effects of newer mobile media exposure on eating, physical activity and obesity needs additional research but is likely to produce similar effects. However, there also are studies suggesting that interactive games can be designed to help improve eating and physical activity behaviors to potentially prevent or reduce obesity. Future research is needed to (1) examine the effects of newer mobile and other digital media exposures on obesity; (2) develop additional interventions to combat the adverse effects of media exposures on obesity, and whether they can be made more effective; (3) most effectively use digital media to prevent and reduce obesity; and (4) uncover how different types of media, media content, and the contexts in which they are experienced, interact to cause obesity and obesity-related behaviors.

FAQs[1]

Is the relationship between time spent with screen media and childhood obesity correlation or causation?

Many studies of screen media and other hypothesized outcomes are correlational — demonstrating that the two factors are related (correlated). Children who spend more time with screen media have greater body fatness at that time and in the future than children who spend less time with screen media. Those studies demonstrate that screen media time is a correlate and risk factor, respectively, but do not prove that it is a cause. A true causal relationship can only be demonstrated with an experiment. These types of experimental studies also have been done for testing the impacts of screen media exposure on obesity. Several randomized controlled trials, the strongest experimental design, have shown that programs to reduce time spent on screens has led to reduced weight gain in children, demonstrating a true cause-and-effect relationship.

How does screen media exposure cause obesity in children?

The evidence to date suggests that screen media exposure causes obesity in children and adolescents via three main mechanisms:

  • Increased eating while using screens, possibly due to the types of high — energy foods and beverages that are consumed with screens, media acting as a trigger or prompt to eating, extending the duration of eating, or distracting from or obscuring feelings of fullness or satiety.
  • Seeing advertising for high-calorie, low-nutrition foods and beverages that alters children’s preferences, purchase requests and eating habits, and
  • Disrupting sleep, which may affect appetite-related hormones, food choices, and more snacking and eating outside of normal mealtimes.

Does smartphone and other new digital media use cause obesity in children?

Most of the research on screen time and obesity was completed before smartphones and other emerging digital media were widely used by children and adolescents. As a result, the specific effects of newer media exposure on eating, physical activity and obesity needs additional research in real world settings. However, many of the mechanisms linking screen media exposure to obesity, such as eating while using screens, advertising, and insufficient sleep, lead us to hypothesize that most emerging digital media, with their increased abilities for interactivity, immersion, involvement, mobility, and timely feedback, could have similar or even more profound effects on causing weight gain in children.

Key Takeaways[1]

  • A large body of research has demonstrated the relationship between greater amounts of screen media use — television, video games, and computers — and obesity in children and adolescents.
  • Randomized controlled trials of behavior change programs in schools and families to reduce time spent on screens have reduced weight gain in children, demonstrating a cause-and-effect relationship.
  • The evidence to date suggests that screen media exposure leads to obesity in children and adolescents via three main mechanisms: increased eating while using screens, leading to greater calorie intake; seeing advertising for high-calorie, low-nutrition foods and beverages that alters
    children’s preferences, purchase requests, and eating habits; and disrupting sleep.

Guidelines for Parents[1]

  • Limit the amount of time your children and teens spend with screen media: Set a daily or weekly limit of screen time for and/or with your child. The strongest evidence for reducing the effects of screen media on obesity comes from randomized controlled experiments of school curricula and family behavioral counseling to reduce total screen time.[2] These studies involved children from age 4 to 13 years of age. The goals in those studies were to limit total screen time, television watching, video game playing, and computer use (excluding computer use for school homework, when applicable) to no more than 7 hours per week in one study and no more than half of the original amount in another study. In one of the studies the children participated in choosing the 7 hours per week goal with the help of their classroom teachers. Non-experimental studies of relationships between screen time and body fatness find no clear optimal threshold of hours of screen time to stay below, with every increment in less screen time being associated with lower risks of obesity. As an added bonus, some experimental studies have shown that reducing screen media time also reduces children’s aggression and their requests to parents to buy them things advertised in screen media.[3]
  • Limit eating with screen media, reduce exposure to food advertising, and ensure that your children and teens get enough sleep:
    • Reduce or eliminate eating with screens. Studies find the children consume large amounts of calories while using screen media.[4] Children tend to consume higher calorie foods and beverages while using screens and watching or playing screen media may act as a reminder or prompt for children to eat. In addition, there is evidence that being distracted by screen media while eating may prolong the eating episode and obscure normal feelings of fullness (for example, eating until the show or game is over or eating until the box, bag or bowl is empty).[5]
    • Monitor your children’s media use for content. Exposure to high-calorie, low-nutrient food and beverage advertisements and marketing influences your children’s preferences, purchase requests and consumption habits.
    • Obesity is also linked to reduced sleep duration. Turn off your children’s media 1–2 hours prior to bedtime, remove the screens from their bedrooms and understand how much sleep children need at different ages of their development in order to ensure that they get an adequate night’s sleep.
  • Set a good example by limiting your own screen media use: Set your own daily or weekly limit of screen time and reduce or eliminate your own eating with screens. Parents are the most important models for their children. Parents can set a good example by limiting their own screen time and not eating with screens. It will make it much easier for your children to learn healthful behaviors if they see you acting the same way you want them to act. It also may help lower your own risk of obesity.

Sources

[1] Robinson, T.N., Banda, J.A., Hale, L., Lu, A.S., Fleming-Milici, F., Calvert, S.L., & Wartella, E. (2017). Screen Media Exposure and Obesity in Children and Adolescents. Pediatrics, 140(140S2). doi:10.1542/peds.2016-1758K

[2] Robinson, T.N., Banda, J.A., Hale, L., Lu, A.S., Fleming-Milici, F., Calvert, S.L., & Wartella, E. (2017). Screen Media Exposure and Obesity in Children and Adolescents. Pediatrics, 140(140S2). doi:10.1542/peds.2016-1758K

  1. Epstein LH, Roemmich JN, Robinson JL, et al. A randomized trial of the effects of reducing television viewing and computer use on body mass index in young children. Arch Pediatr Adolesc Med 2008;162:239-45.
  2. Gortmaker SL, Peterson K, Wiecha J, et al. Reducing obesity via a school-based interdisciplinary intervention among youth: Planet Health. Arch Pediatr Adolesc Med 1999;153:409-18.
  3. Robinson TN. Reducing children’s television viewing to prevent obesity. JAMA 1999;282:1561-7.
  4. Robinson TN, Borzekowski DLG. Effects of the SMART classroom curriculum to reduce child and family screen time. Journal of Communication 2006;56:1-26.

[3] Robinson, T.N., Banda, J.A., Hale, L., Lu, A.S., Fleming-Milici, F., Calvert, S.L., & Wartella, E. (2017). Screen Media Exposure and Obesity in Children and Adolescents. Pediatrics, 140(140S2). doi:10.1542/peds.2016-1758K

  1. Robinson TN, Saphir MN, Kraemer HC, Varady A, Haydel KF. Effects of reducing television viewing on children’s requests for toys: A randomized controlled trial. J Dev Behav Pediatr 2001;22:179-84.
  2. Robinson TN, Wilde ML, Navratil LC, Haydel KF, Varady A. Effects of reducing children’s television and video game use on aggressive behavior: A randomized controlled trial. Arch Pediatr Adolesc Med 2001;155:17-23.

[4] Robinson, T.N., Banda, J.A., Hale, L., Lu, A.S., Fleming-Milici, F., Calvert, S.L., & Wartella, E. (2017). Screen Media Exposure and Obesity in Children and Adolescents. Pediatrics, 140(140S2). doi:10.1542/peds.2016-1758K

  1. Matheson DM, Wang Y, Klesges LM, Beech BM, Kraemer HC, Robinson TN. African-American girls’ dietary intake while watching television. Obes Res 2004;12:32S-7S.

[5] Robinson, T.N., Banda, J.A., Hale, L., Lu, A.S., Fleming-Milici, F., Calvert, S.L., & Wartella, E. (2017). Screen Media Exposure and Obesity in Children and Adolescents. Pediatrics, 140(140S2). doi:10.1542/peds.2016-1758K

  1. Robinson TN, Matheson DM. Environmental strategies for portion control in children. Appetite 2015;88:33-8.

The analysis, conclusions, and recommendations contained in each paper are solely a product of the individual workgroup and are not the policy or opinions of, nor do they represent an endorsement by, Children and Screens: Institute of Digital Media and Child Development.

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