This article assesses the role played by media in contributing to the current epidemic of childhood obesity. Electronic media use, often referred to as screen time, is significantly correlated with child adiposity. Although the causal mechanism that accounts for this relationship is unclear, it is well established that reducing screen time improves weight status. Media advertising for unhealthy foods contributes to obesity by influencing children’s food preferences, requests, and diet. Industry efforts have failed to improve the nutritional quality of foods marketed on television to children, leading public health advocates to recommend government restrictions on child-targeted advertisements for unhealthy foods.
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Electronic media use is significantly positively correlated with adiposity in children.
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Interventions reducing screen media use by children (eg, eliminating television from children’s bedrooms; turning off the television while eating) have been associated with improvement in child weight status.
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Children’s exposure to media marketing messages for unhealthy food products is well established as a significant contributor to childhood obesity.
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Food industry self-regulation initiatives have had only negligible effects in improving the nutritional quality of foods advertised to children.

Numerous elements contribute to childhood obesity. Regular consumption of a calorie-dense, nutrient-poor diet and inadequate moderate-to-vigorous physical activity are key risk factors. Media use has also been established as a strong correlate of childhood obesity. This relationship was first identified in the 1980s and has been corroborated by dozens of studies since then. It is often assumed that the sedentary nature of television viewing, traditionally the largest component of young people’s time spent with media, is the mechanism underlying the relationship. The presumption holds that heavy media users are transformed into so-called couch potatoes who devote insufficient time to exercise because their eyes are too often glued to the screen. Consistent with this perspective, the US Department of Health and Human Services specified a national objective of reducing television viewing to combat obesity in its Healthy People 2010 target goals.
However, more recent evidence has focused increasing attention on the role of food marketing to children as a causal factor contributing to childhood obesity. Given the significant amount of time children spend watching television, they inevitably encounter large amounts of commercials for food products. Televised food advertising is dominated by high-density, low-nutrient products that the public typically labels as junk food. Advertising for unhealthy food products has also migrated to new media venues frequented by children and teens, such as the Internet. Exposure to commercial promotions in the media wields influence on children’s food product preferences, requests, diet, and ultimately their diet-related health. Advertising exposure may be the principal causal mechanism that explains why screen time is significantly correlated with childhood obesity, rather than the widely presumed couch-potato hypothesis.
This review article surveys the research that documents children’s patterns of media use, analyzes the evidence that shows the association between young people’s screen time and weight status, considers the role of food marketing as a contributor to childhood obesity, and evaluates recent intervention efforts intended to reduce children’s screen time and/or exposure to advertising messages for unhealthy food products. Overall conclusions and possible solutions to reduce the role of media as a contributor to childhood obesity are also discussed.
Screen time within the context of obesity prevention
Screen time is a term meant to represent an individual’s use of electronic mass media, including television viewing, video and computer game playing, DVD viewing, Internet use, and other online activities. Media use in childhood is primarily a means of entertainment, and hence is engaged in mostly during unstructured time outside of school hours. Public health researchers originally conceived of screen time as a sedentary activity, which holds obvious implications for displacing time that might otherwise be devoted to physical exercise.
Given the recent proliferation of mobile technologies and digital media, screen time can now occur from almost any geographic location via highly portable video-enabled and Internet-enabled devices such as iPads, iPods, and smartphones. The use of these mobile technologies reduces the likelihood that the user is necessarily sedentary while engaging in screen-related activities, thus rendering the construct of screen time a less precise and reliable assessment of time spent in sedentary pursuits. However, regardless of how screen time may be defined and quantified, there is little doubt that children and adolescents spend significant time with screen-based media, and that media use by youth has increased as mobile technologies have become more readily available and accessible.
Screen Media Diet: Infants and Preschoolers
Survey data indicate that television viewing begins at a young age, and has surged as a function of the recent expansion in programming targeted specifically at infants. More than half (59%) of children less than 2 years of age watch television on an average day, despite the American Academy of Pediatrics recommending no media exposure before the age of 2 years. Children average 2.2 hours of viewing per day at age 1 year, increasing to 3.6 hours per day by 3 years of age. By age 5 years, more than 60% have used handheld games, 81% have played console games, and 90% have used a computer.
Among children less than 8 years of age, most screen time is still spent watching television (74% of media time), followed by the use of computers (13%), video games (10% of the time), and , cell phones/iPods/iPads (4%). Nearly half (47%) of children aged 5 to 8 years have a television set in their bedroom, including 30% of children less than 2 years old. Overall, the average daily time that children less than 8 years old spend with television and DVDs is estimated to be about 1:40, with roughly another half hour devoted to playing video, computer, or handheld games.
Screen Media Diet: School-aged Children and Teens
The amount of time spent with media is also increasing for older children and adolescents. From 2005 to 2010, media use for those aged 8 to 18 years increased by more than an hour a day, moving from 6:21 to 7:38 daily. As with younger children, most screen time was devoted to television. Older children and teens are more likely to multitask, in terms of engaging multiple media venues simultaneously, as well as engaging in activities such as homework while also using mass media. Older children and teens spend more time with media than in any other waking activity. As Rideout and colleagues observed, using media comprises a full-time job for youth, accounting for 7.5 hours per day, 7 days per week.
Although there may be some benefits associated with children’s screen media use, such as learning from educational programs, there is also significant risk for a range of adverse side effects. Exposure to certain types of media portrayals may increase child viewers’ aggressive behavior, decrease the age of first sexual intercourse, and contribute to gender and ethnic group stereotyping in children and teens. However, regardless of the type of content viewed, heavy screen media use correlates significantly with overweight and obesity in children.
Association between screen time and obesity in children and adolescents
A systematic review of the published research evidence linking television exposure with adiposity was conducted in 2006 by the Institute of Medicine (IOM). The IOM identified more than 60 studies conducted over roughly the past 20 years that converged to show a small but statistically significant relationship between television exposure and child obesity. Studies were evaluated for methodological strength, and the greater the study’s rigor, the greater the likelihood that it showed a significant relationship between these variables. Since the IOM review was published, numerous large-scale epidemiologic studies have emerged to further corroborate this relationship.
Data from cross-sectional and longitudinal studies yield the same pattern of results. One review of research reported that, in 18 of 22 longitudinal studies, more hours of media exposure predicted increased weight over time. Although a small minority of studies have produced nonsignificant results, the null findings are most often attributed to limitations in defining and measuring time spent with screen media, among other confounds. One of these complications involves video game use.
Video Games
By most definitions, screen time encompasses video game play. However, studies that focused on video game play have been less consistent in showing correlations between screen time and adiposity, compared with research centered on television use. Fewer studies have specifically targeted video game play, and, although some of these yield evidence of associations with obesity, others do not. A recent review of evidence found that there were more studies that produced no significant association between video game play and obesity than had yielded significant correlations. One of the most obvious complications here is that video games are not as inherently sedentary as watching television, especially when exercise-oriented games such as Dance Dance Revolution are considered.
Possible Causal Mechanisms
The direction of causality in the relationship between screen time and obesity could potentially flow either way. That is, overweight individuals might tend to stay home and use media more than physically active people, hence accounting for the relationship between screen time and adiposity. Although plausible, this possibility is rebutted by several types of evidence. Twelve of 15 longitudinal studies that measure television use at time 1 and weight status at 1 or more subsequent points in time produced significant associations with weight gain over time. In addition, an experimental intervention that reduced screen time over a 6-month period found significantly less increase in BMI and other measures of adiposity, compared with a control group. The totality of evidence suggests that greater amounts of time spent with screen media lead to weight gain and the risk of obesity, rather than the other way around. What is less clear is the underlying mechanism that accounts for that relationship.
Data that merely correlate media use with childhood obesity do not clarify whether weight gain may be a function of the largely sedentary nature of the activity (ie, displacement of physically active time), or might instead be the result of some other factor/s. There are several incongruities that pose challenges for the couch-potato hypothesis. The American Academy of Pediatrics has observed that, although many studies find that physical activity decreases as screen time increases, many others do not. Within child care settings, for example, 1 study found that youngsters attending day care centers with high use of electronic media had greater sedentary behavior than children in centers with low electronic media use, but 2 other comparable studies found no association between these variables.
Higher levels of screen time do not always correlate with lower levels of physical activity. An IOM review reported only 14 of 20 studies that analyzed these variables found a significant relationship (see Table 5-22 in Ref. ). It is common for studies to find only small proportions of children that concomitantly experience high screen time and low physical activity. For example, in one study of children aged 4 to 11 years using National Health and Nutrition Examination Survey (NHANES) data (N = 2964), less than one-quarter of boys (23.7%) and one-third of girls (29.1%) were in this category. In addition, most studies that control statistically for amount of physical activity in examining the relationship between screen time and obesity still produce a significant correlation.
Perhaps the most telling evidence is provided by a study that separated time spent watching television into 2 categories, 1 with and 1 without commercial advertisements included. The findings were clear. Time spent viewing commercial television was significantly correlated with BMI, whereas time watching noncommercial television was not. The overall evidence in this area clearly suggests that the role of media in contributing to childhood obesity entails more than simply displacing time that would otherwise be devoted to exercise. Another factor that may play a role involves snacking that occurs during television viewing time. However, the most likely alternative explanation for the linkage between screen time and adiposity involves the influence of advertisements for unhealthy foods that are widespread in media consumed by children.
Association between screen time and obesity in children and adolescents
A systematic review of the published research evidence linking television exposure with adiposity was conducted in 2006 by the Institute of Medicine (IOM). The IOM identified more than 60 studies conducted over roughly the past 20 years that converged to show a small but statistically significant relationship between television exposure and child obesity. Studies were evaluated for methodological strength, and the greater the study’s rigor, the greater the likelihood that it showed a significant relationship between these variables. Since the IOM review was published, numerous large-scale epidemiologic studies have emerged to further corroborate this relationship.
Data from cross-sectional and longitudinal studies yield the same pattern of results. One review of research reported that, in 18 of 22 longitudinal studies, more hours of media exposure predicted increased weight over time. Although a small minority of studies have produced nonsignificant results, the null findings are most often attributed to limitations in defining and measuring time spent with screen media, among other confounds. One of these complications involves video game use.
Video Games
By most definitions, screen time encompasses video game play. However, studies that focused on video game play have been less consistent in showing correlations between screen time and adiposity, compared with research centered on television use. Fewer studies have specifically targeted video game play, and, although some of these yield evidence of associations with obesity, others do not. A recent review of evidence found that there were more studies that produced no significant association between video game play and obesity than had yielded significant correlations. One of the most obvious complications here is that video games are not as inherently sedentary as watching television, especially when exercise-oriented games such as Dance Dance Revolution are considered.
Possible Causal Mechanisms
The direction of causality in the relationship between screen time and obesity could potentially flow either way. That is, overweight individuals might tend to stay home and use media more than physically active people, hence accounting for the relationship between screen time and adiposity. Although plausible, this possibility is rebutted by several types of evidence. Twelve of 15 longitudinal studies that measure television use at time 1 and weight status at 1 or more subsequent points in time produced significant associations with weight gain over time. In addition, an experimental intervention that reduced screen time over a 6-month period found significantly less increase in BMI and other measures of adiposity, compared with a control group. The totality of evidence suggests that greater amounts of time spent with screen media lead to weight gain and the risk of obesity, rather than the other way around. What is less clear is the underlying mechanism that accounts for that relationship.
Data that merely correlate media use with childhood obesity do not clarify whether weight gain may be a function of the largely sedentary nature of the activity (ie, displacement of physically active time), or might instead be the result of some other factor/s. There are several incongruities that pose challenges for the couch-potato hypothesis. The American Academy of Pediatrics has observed that, although many studies find that physical activity decreases as screen time increases, many others do not. Within child care settings, for example, 1 study found that youngsters attending day care centers with high use of electronic media had greater sedentary behavior than children in centers with low electronic media use, but 2 other comparable studies found no association between these variables.
Higher levels of screen time do not always correlate with lower levels of physical activity. An IOM review reported only 14 of 20 studies that analyzed these variables found a significant relationship (see Table 5-22 in Ref. ). It is common for studies to find only small proportions of children that concomitantly experience high screen time and low physical activity. For example, in one study of children aged 4 to 11 years using National Health and Nutrition Examination Survey (NHANES) data (N = 2964), less than one-quarter of boys (23.7%) and one-third of girls (29.1%) were in this category. In addition, most studies that control statistically for amount of physical activity in examining the relationship between screen time and obesity still produce a significant correlation.
Perhaps the most telling evidence is provided by a study that separated time spent watching television into 2 categories, 1 with and 1 without commercial advertisements included. The findings were clear. Time spent viewing commercial television was significantly correlated with BMI, whereas time watching noncommercial television was not. The overall evidence in this area clearly suggests that the role of media in contributing to childhood obesity entails more than simply displacing time that would otherwise be devoted to exercise. Another factor that may play a role involves snacking that occurs during television viewing time. However, the most likely alternative explanation for the linkage between screen time and adiposity involves the influence of advertisements for unhealthy foods that are widespread in media consumed by children.
The role of food marketing in childhood obesity
As indicated earlier, children engage in heavy media use, with television still dominant among an increasingly diverse range of screen media. Given that commercial messages are pervasive in most television content, it is inevitable that child viewers are exposed to large numbers of advertisements, including many for food products. According to the Federal Trade Commission, children aged 2 to 17 years see roughly 5500 televised food advertisements per year, or about 15.1 per day. Commercials for food products have long been a staple in children’s television programming, and the featured items are typically low-nutrient, calorie-dense fast foods, candies, snacks, and sugared cereals.
Food Advertising to Children
Food marketers invest nearly $2 billion annually in child-targeted advertising, with the largest share devoted to television advertisements. Studies of advertising content document the prevalence of obesogenic foods in television advertising targeted at youth. For example, 2 out of every 3 cereals (66%) advertised to children fail to meet nutritional standards with regard to added sugar. Nearly all (98%) food advertisements seen by children and 89% viewed by adolescents are for products high in fat, sugar, or sodium ( Fig. 2 ). In contrast, healthy foods that should be part of a regular diet are almost never advertised to children.
As new media have evolved and attracted children’s interest, advertisers have migrated to these venues along with youth audiences. Food marketers have established Internet Web sites that offer games and other attractive entertainment options for children, creating a media experience that is a commercial promotion. Product-based so-called advergames allow children to play virtual games with popular brand characters such as Chester Cheeto or Tony the Tiger, blurring boundaries between commercial and entertainment content in a manner that federal regulations prohibit on television. More than half of the food advertisements on children’s television programs now promote such product-based Web sites.
Other innovations in marketing food products to children include in-game advertising, placed within video games ; viral marketing, in which consumers share product-related messages with friends to receive rewards ; and promotional activities in schools. Collectively, these efforts comprise a significant expansion of the overall commercial environment targeted at youth, which many now describe as the commercialization of childhood.
Effects of Food Advertising on Children
Food marketing plays a significant role in shaping children’s nutritional knowledge, eating habits, and weight status. Heavy exposure to televised food advertising is associated with nutritional misperceptions: the greater the exposure to food advertising, the greater the likelihood that unhealthy items will be judged as healthy and nutritious. Numerous experiments show short-term effects on children’s attitudes and product preferences for foods. Amount of television exposure is positively correlated with children’s ability to correctly identify product brands and with their consumption of advertised brands.
The most comprehensive review of studies examining the effects of food marketing on children was conducted by the IOM in 2006. The IOM report concluded that (1) there is strong evidence that advertising influences the short-term food consumption of children aged 2 to 11 years; (2) there is moderate evidence that advertising influences the regular diet of children 2 to 5 years of age, and weak evidence (ie, more studies are needed) that it influences children 6 to 11 years of age; and (3) there is strong evidence that exposure to advertising is associated with adiposity in children 2 to 11 years of age and teens 12 to 18 years of age. The report summarized its findings by observing that “food and beverage marketing practices geared to children and youth are out of balance with healthful diets, and contribute to an environment that puts their health at risk.” (p374)
The conclusion that advertising to children works as intended is clear, if unremarkable. In an ideal world, parents would refuse children’s purchase influence requests for unhealthy foods, negating much of the impact of advertising. In practice, parents have a high rate of yielding to children’s requests. Furthermore, most children begin to purchase snack foods with their own money as early as 8 years of age. Thus, given that children’s exposure to media marketing messages for unhealthy food products is now well established as a significant contributor to childhood obesity, this article reviews possible tactics and strategies that might mitigate the health risks posed in this area.

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