Introduction

US consumers spent $29.1 billion on video games in 2017, a $10 billion increase over the last 5 years, yet relatively little is documented in the scientific literature on the effects of video game play on young players [1]. Video games, an electronic game in which players control images on a video screen, first came into the world 60 years ago with two lines and a bouncing dot in “Tennis for Two” [2]. The popularity of this rudimentary game led to the development of computer devices specifically for games, called consoles, in 1972, followed by hand-held devices in 1989, 3-D gaming in 1995, motion-activated active video games (called “exergames”) that require bodily movement to control on-screen play, and online gaming [3]. The additional use of screens in daily life is a major concern as high amounts of television (TV) viewing have been linked to higher obesity prevalence in children [4] and adverse energy-balance related behaviors including consumption of unhealthy foods while viewing TV [5] and lower physical activity, as screen time has traditionally been a sedentary behavior [6]. Research assessing the impact of video game play on young players is needed to keep pace with a rapidly evolving video game industry that remains highly popular and increasingly complex.

At a time when youth are surrounded by a multitude of screen and technology options, the popularity of video games has stood the test of time. The majority of adolescents (13–17 years) have smart phones (95%), and 90% report they play video games on a cellphone, console, or computer [7•]. Accordingly, video games may be better called “digital games” as they reach diversified platforms like smartphones and tablets and push the limits of immersive gaming through virtual reality and augmented reality. Time spent playing video games is quickly exceeding TV viewing in children [8], potentially due to the virtual and immersive social interaction [9] and the proliferation of inexpensive or free digital games on a variety of devices. This evolution has concerned the public health and lay community as video games have been linked to poor social development and delayed cognition in children as young as preschool [10]. As for physical development, previous evidence has found traditional seated video games to be associated with increased caloric intake [11] and a 2-fold increase in obesity per hour per day played [12].

Early reports in 2004, including a meta-analysis and a cross-sectional examination, found children who had a higher weight status reported more frequent video game play [13, 14]. Interest in this sedentary behavior continued with a meta-analysis in 2008 that found inconsistent results with video game play and obesity in children, though when video games were combined with TV, there was a significant positive association [15]. Around this time, video games were becoming repurposed to utilize for positive health-related changes, most notably exergames that required the player to engage in upper and/or lower body movement [16]. No longer solely a sedentary pastime, exergaming was investigated in early studies as a genre of video game that indicated promise for improving players’ physical activity levels [17] and consequently reduce body fat and obesity [18].

Prior systematic reviews have focused on relationships of screen time in general with children’s adiposity without specifically focusing on video game play. For example, a recent systematic review that examined 40 studies published from 2010 to 2017 indicated a positive association of screen time with adiposity in children and adolescents in 85% of the studies (mostly cross-sectional, though six longitudinal and one intervention was included), yet this review did not specifically examine video game play isolated from other screen activities nor did it specify effects of newer generation games like exergames on obesity [19]. The increasing exposure and advances in video games in the past 5 years, coupled with the historically high prevalence of childhood obesity, warrant an updated review of the association of video game play with childhood obesity. Therefore, the aim of this study was to critically review potential associations between video game play and obesity in children by examining recently published observational studies and interventions. Accordingly, we sought to answer three main questions.

  1. 1.

    What is the current state of observational evidence (cross-sectional and prospective data published in the most recent 5 years) on the relationship between video game play and childhood obesity? (Part 1)

  2. 2.

    To what extent do video games serve as an effective intervention tool for healthy weight in children? (Part 2)

  3. 3.

    What gaps still exist in understanding the relationship between video games and obesity, in particular energy balance behaviors? (Part 3)

Part 1: Scoping Review: Video Games and Obesity in Children

Methods

A systematic search of PubMed, PsycINFO, and CINAHL databases was conducted for studies published in the English language from December 2013 to November 2018. The search terms included a combination of MeSH Terms or engine specific search terms of video games (video gam*, active video gam*, exergam*) and obesity (obesity, adiposity). Observational studies in a child population (average age 2.0–18.9 years old) that assessed the relationship between obesity and video games (or vice versa) were included. Studies that included video games as a mediator or moderator of an association between a predictor variable (obesity-related behaviors such as sleep or diet) and obesity were also included [20•, 21]. Studies were excluded if they were conducted in children with a chronic condition (such as autism) or in adults, used a non-observational study design (such as case study, intervention, qualitative study, or systematic review), involved video game development (such as characters or features of video games), or were specific to video game addiction tendencies.

Two authors (CLK and EDJ) independently screened abstracts retrieved from the initial search. Full-text articles of selected abstracts were independently assessed for inclusion by the same authors. Any disagreement in eligibility after the abstract or full-text process was resolved by the third author (AES). Reference lists of the included articles were scanned for relevance. Data were extracted into a pre-piloted form including type of study, population characteristics (age, race, setting, and country), study methodology, measures of video game play and obesity, and main results.

Results

The selection of studies is detailed in Fig. 1. Three hundred and twenty articles, including 319 articles from initial search and one article through reference lists of included full-text articles, were identified. After removing 84 duplicates, 236 original articles were screened. In abstract screening, 164 abstracts did not pass screening as they included children with chronic conditions (n = 17), were in adults (n = 7), were interventions or qualitative studies (n = 52), were systematic reviews or meta-analyses (n = 43), assessed another media device (n = 4), were focused on video game addiction (n = 3), or were the outside of the scope of the review (n = 38). The 38 abstracts that were outside of scope included those with no measure of video game play or assessed general sedentary behaviors (n = 19), no measure of obesity (n = 7), validation studies (n = 4), assessed parental habits on obesity (n = 3), were not in English (n = 2), assessed only children who had obesity introducing no variability (n = 1), were reporting on child-care general screen time policies (n = 1), or were an education guide for parents (n = 1). Forty-three systematic reviews or meta-analyses from original screening of 236 articles were assessed for eligibility in part 2. Thirty-nine articles were excluded as they assessed broad energy balance behaviors (n = 14), were outside of scope (n = 12), addressed only video game play or obesity but not both (n = 7), or were overall opinion pieces (n = 6). The remaining 4 articles are discussed in part 2: they pertain to exergames [22,23,24] or general video games [25••], and they present aggregate findings.

Fig. 1
figure 1

Flow chart of study selection

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Seventy-two articles remained for full-text screening. Forty-six articles did not pass full-text screening as many articles (n = 22) assessed aggregate screen time or combined TV/video games without specifically reporting on video game play separate from the other types of screen time. Twenty-six articles were ultimately selected for data extraction [20•, 21, 26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49].

Descriptive characteristics of the included articles are reported in Table 1. In total, 25 cross-sectional studies and one longitudinal study with follow-up of 2 years were identified. Sample sizes of included studies ranged from 91 to 24,800 (median 938), and half of studies were conducted in Canada (n = 7) or the USA (n = 6). The youngest age range included was 2–13 years [29], as most focused on the 10–12 year old age range [28, 30, 36, 45,46,47, 49] or included a broad age range of adolescents ages 11–18 years old [20•, 26, 27, 32, 37, 39, 42]. The oldest data were collected in 2001 [35], and the most recent data collection was 2015 [48], with all other studies occurring between these time points.

Table 1 Descriptive characteristics of included studies in part 1 (n = 26)
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Articles were grouped by characterization of video game play, including total hours of video game play in general (n = 11), video game play on weekdays (n = 8), video game play before bed (n = 5), video game play during school holiday (n = 1), and video game presence in the child’s bedroom (n = 2). One article was reported twice in Table 1 as the study reported both on video game play before bed and presence of a video game console in the bedroom [49], and two articles came from one research study [39, 40].

Fourteen of the 26 articles (53%) reported no association between video game play and obesity, whereas 12 reported a positive association. No article found an inverse relationship between video game play and obesity. In the 11 articles that assessed duration of video game play in general, seven articles did not find an association in adjusted models [21, 31, 33,34,35, 37, 43] while the other four articles reported significant associations [26, 28, 38, 47]. Two of these significant findings only found associations in boys or girls but not overall; one article reported that video game hours played was positively associated with percent body fat in boys but not girls [28], while the other article found baseline video game/computer game hours was associated with larger BMI gains in girls but not in boys [26]. Of the other two articles reporting significant associations, one article found that a combined media use score (including use of video game/computer/mobile/tablet) was associated with a higher risk of obesity (OR 3.24 [95% CI 1.42–7.27]) [47] though video game use itself was not assessed. Another article found children who had overweight/obesity had more minutes of video game play per day (36.3 ± 1.7 min/day) compared to children who were normal weight (8.7 ± 1.7 min/day) in adjusted models [38].

For the eight articles specifically reporting on weekday use of video games, six articles (75%) reported no significant association between video game play and obesity [29, 32, 36, 41, 42, 44]. Two of the non-significant article found positive associations between video game play on weekdays and obesity in crude models, but this association was no longer significant in models adjusted for sociodemographic variables or other health behaviors [42, 44]. For the two articles that did observe significant associations between weekday video game play and obesity, Gates et al. (2013) found that more boys who were overweight or had obesity played video games/used the internet after school more than 2 h per day than boys who were normal weight in a sample of First Nation youth in Ontario [27]. Kenney and Gortmaker (2017) found children with 5+ h of other screen viewing (including video game play) on weekdays had a higher risk of obesity in adjusted models (OR 1.34 [1.21, 1.71]) [48]. Of the five articles examining video game play before bedtime, one article reported no association between video games before bed and obesity [30], with the other four reporting significant associations with frequency of video games [39], access to video games [49] or via a mediation model including poor sleep [20•, 40]. Only two articles reported video game presence in the child’s bedroom, and both found that access to video games in the bedroom was associated with higher weight [45, 49].

Few articles reported on the indirect relationships between video gaming and obesity via other health behaviors. Preliminary evidence indicated that video game play may be related to higher carbohydrate intake [21] and insufficient sleep [20•, 39], but this evidence is limited.

There were patterns distinguishing the articles that did or did not observe a significant association of video game play with obesity. Articles that found a positive association between video game play and obesity typically collected data after 2012 [20•, 45,46,47,48,49] except for one where data were collected in 2009 [39, 40]. Articles reporting a positive association also typically combined video games with other screen devices (namely mobile phones and computer use), making it difficult to parse out the independent relationship of video game play and obesity aside from these other types of screen time [47, 48]. However, articles that combined video game play with computer or other devices that collected data prior to 2012 found little or no association [30, 32, 33, 35, 36]. There were no consistent differences in results based on whether obesity was classified by self-report or objectively measured. There is limited comment to be made on the longitudinal influence of video games on the incidence of obesity as only one longitudinal study was identified, and this study drew upon data collected more than 10 years ago [26].

Summary

Overall, there is inconsistent evidence of the relationship between video gaming and obesity, with just over half of articles indicating no significant association between video game play and obesity. Longitudinal studies that report specifically on video game play (exclusive of other screen time) and include newer generation video games like exergames and mobile games is required to understand relationships between modern video game play and obesity in this quickly evolving technological landscape. Further, the role of video game play on obesity-related behaviors warrants further attention.

Part 2: Video Games as an Intervention for Healthy Weight (Review of Reviews)

In recent years, video game play has been a behavioral target for weight reduction and attenuation among children and adolescents—on the one hand, to reduce sedentary video game play and, conversely, to manipulate traditionally sedentary video games into physically active game play. This section summarizes the systematic reviews published from 2013 to 2018 that utilized video games in weight reduction interventions or weight attenuation, including 4 reviews identified in the literature search and 4 identified by the authors’ files. Descriptive characteristics of the included reviews are shown in Table 2.

Table 2 Descriptive characteristics of included studies in part 2 (n = 8)
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Current State of Evidence

Reducing Video Game Play and Screen-Time for Weight Reduction

Two systematic reviews published in the past 5 years surveyed randomized controlled trials (RCTs) that targeted screen time reduction in children and adolescents; both reviews revealed that most interventions have failed to effectively reduce screen time [25••, 50]. Without effectively changing the behavioral target, it is challenging to examine the influence of reduced screen time (or, more specifically, reduced time spent playing video games) on weight.

Wu et al. identified 12 trials published prior to September 2015; pooled mean differences indicated no significant change in youths’ screen time nor a change in BMI [25••]. Marsh et al. (2014) identified 17 trials of family-based RCTs to reduce sedentary time in children ages 2–18 years that actively involved parents; notably, these trials were published prior to April 2012 [50]. Most trials restricted screen time as the main strategy to reduce sedentary time, with the interventions delivered through counseling/group sessions, TV monitoring devices, or the promotion of physical activity to displace sedentary screen time. Two trials created a behavioral contingency where the child was required to be physically active to watch TV, and two trials examined exergames as a strategy to incorporate physical activity into video games. There were inconsistencies in the effectiveness of these interventions to reduce sedentary time: ten trials significantly reduced sedentary time, whereas seven did not. Sixteen of the 17 trials reported body weight or body composition as a secondary outcome. Two RCTs that were described as effective for weight loss included a 2-year screen time reduction intervention for preschool-aged children (n = 70) that significantly reduced BMIz compared to a monitoring control group [54] and a 6-month exergaming intervention that reduced BMIz and fat mass among children ages 10–14 years (n = 322) who received exergames vs. those who received sedentary video games [55]. Findings on weight outcomes from the other 14 trials were not reported.

Using Video Games to Reduce Weight

Contrary to restricting screen time, video games have also been examined as potential tools to reduce weight and improve obesogenic behaviors in children and adolescents, using the games to teach or reinforce healthy eating strategies or to engage the player in physical activity. Lu et al. (2013) conducted a systematic review on the effects of health video games on childhood obesity and identified 28 studies published between 2005 and 2013 [52]. Three published trials involved health games that researchers developed to promote healthy eating; two of these trials effectively improved eating habits including fruit and vegetable consumption whereas one did not; however, none affected obesity outcomes. The other 25 video games examined were exergames, which has become the predominant video game genre being examined for potential weight-related outcomes.

Exergames may offer opportunities for moderate-to-vigorous physical activity (MVPA), which the Physical Activity Guidelines for Americans concluded is associated with reduced risk of excess weight gain in children [56]. The Youth Compendium of Physical Activities, compiled from a literature search of published energy expenditure data in youth, reported physical activity intensities from exergame play based on the specific type of exergame and the age range; intensities ranged from the lowest of 1.3 Metabolic equivalents of task (METs) indicating light intensity activity for Nintendo Wii muscle conditioning exergames to the highest of 7.7 METs indicating vigorous intensity physical activity for action running exergames [57]. Of the 116 intensity classifications for exergames (29 types of exergames cataloged across 4 age groups), 8% were classified as vigorous, 52% as moderate, and 48% as light intensity. Further, a meta-analysis of 35 studies conducted by Gao et al. (2015) indicated that exergames elicited small to moderate increases in intensity based on heart rate above laboratory-based exercises activities such as brisk walking and biking, but exergaming was lower in intensity than laboratory-based running [23]. Other systematic reviews and meta-analyses published prior to 2013 similarly indicated that exergaming can reach levels of light-to-moderate intensity physical activity [58,59,60]. Therefore, exergames have been examined in recent years a potential physical activity tool to reduce excessive weight gain among children and adolescents.

Six systematic reviews were identified that surveyed the effects of exergaming interventions on change in weight among children and adolescents and included in this analysis [22,23,24, 51, 52, 53••]. In general, authors across the systematic reviews acknowledged that the evidence for exergaming affecting obesity outcomes is inconclusive. As expected, there was significant overlap in the included studies across the systematic reviews. The most recently published systematic review was from Zeng and Gao (2016), which identified 12 studies published from January 2010 to May 2016 that were specifically conducted in overweight youth or youth with obesity [53••]. Seven RCTs examined adiposity as an outcome variable, with four of these RCTs demonstrating a significant improvement in BMI, body composition, or body fat but the other three RCTs observing no significant changes. Similarly, Gao and Chen (2014) identified 34 studies of field-based exergaming with variable effects on obesity-related outcomes, with the authors pointing out issues related to design, measurement, and methodology that produced inconsistent results [24]. LeBlanc et al. (2013) reviewed 51 unique studies published from 2006 to 2012 and identified six RCTs and three interventions that examined changes in weight [51]. Four of the six RCTs attenuated weight gain, including all three RCTs focused exclusively on overweight youth or youth with obesity and one RCT that included normal weight participants. None of the three non-RCT intervention studies observed weight loss among youth who were normal weight or overweight. Lamboglia et al. (2013) identified nine exergaming studies including eight that measured obesity; two of these studies observed significant reductions in an obesity outcome [22]. Finally, Lu et al. (2013) reviewed 14 studies of 28 health video games published between 2005 and 2013 and observed significant reductions in obesity in six studies, and all six of the effective studies utilized exergaming [52].

Exergaming has been incorporated into two published pediatric weight loss trials [61, 62]. Trost et al. conducted a group-randomized clinical trial comparing a 16-week family weight management program with or without exergaming among 75 overweight children aged 8 to 12 years [61]. The exergaming group received a game console and two exergames to play at home, and this group significantly reduced BMIz by − 0.12 and increased MVPA by 1 h/week compared to the non-exergaming group. A second study was a pilot feasibility study that assigned 48 children between 8 and 16 years of age to an “Exergaming for Health” multidisciplinary weight management program involving 10 weekly 2-h sessions, with 1 h consisting of exercise/exergaming, and 1 h of nutrition instruction [62]. Exergames were housed at the recreation center where families attended weight management sessions, and participants were encouraged to engage in 3 h of additional exercise each week outside of the sessions. The 40 children who completed the program attained an average BMIz reduction of − 0.07; however, there was no comparator group. The manuscript did not report the extent to which children played exergames outside of the group sessions, so it is not possible to examine the influence of exergame play on children’s weight loss. Both studies failed to meet thresholds of BMIz reduction considered to be clinically meaningful (≥ 0.25 units) [63].

Newer mobile-based video games such as geocaching and augmented reality games like Pokemon Go have been recently investigated as strategies to promote physical activity, but there were no systematic reviews available. Gamification has also been identified as a potential strategy to promote healthy behaviors. A systematic review that identified 19 empirical studies (4 in the pediatric population) on the effect of gamification on health and well-being observed improvements in children’s fruit and/or vegetable consumption, but weight changes were not reported [64]. However, gamification does not meet the definition of a video game; gamification applies game design principles such as competition or rewards to a non-game context, without involving a fully immersive video game [65•].

Part 3: Areas for Future Research

Overall, there is inconclusive evidence that video games directly influence childhood obesity, from both observational and intervention studies. There are multiple opportunities for future areas of research into video game play and its potential effects on childhood obesity, including better capturing quality or content not just quantity of video game play as related to obesity and related behaviors. Video games may positively influence snacking and unhealthy energy intake, which can lead to positive energy balance and excess weight gain [21, 66]. Similar mechanisms have been proposed for TV viewing, which may evoke similar sedentary behavior as traditional console-based sedentary video game play but differ from mobile-based gaming [50, 67, 68]. There is a growing interest in video game play before bedtime due to delaying sleep onset and shortening sleep duration, as youth with shorter sleep duration have been shown to consume more calories [69, 70] and have higher prevalence of obesity [71].

Co-participation and within game socialization are areas to be investigated as social interaction is a main feature of many video games and may differentially impact obesity-related behaviors [72]. Two-thirds of parents play video games with their child at least once a week, thus reducing parental screen time may influence child video game play [1]. This area warrants additional research.

Understanding the extent to which exergames may be integrated into comprehensive behavioral change programs is warranted, as coupling exergames with nutrition education and psychosocial counseling has produced reduction in children’s weight status [62]. The assessment of video game play needs to extend into other popular modalities such as esport leagues, which are competitive video game leagues including both individual and team options [73]. Esports are quickly growing popularity and projected to reach a $23.5 billion industry itself by 2020 [74]. The mass use and social acceptability of video gaming may have downstream influences on energy-related behaviors on children [75].

While this review did not specifically examine video game addiction, further investigations are needed into pathways of video game addiction and potential links to obesity [72]. Video game addiction has been associated other negative outcomes, including lower school performance and higher substance use in adolescence [76] and problematic gaming behaviors later in life [77].

Strengths of the current body of literature include that there are several reports of video game play and obesity specifically in children and adolescents. The relationship of video game play with other obesity metrics (such as body fat percentage) is also beginning to be reported in the scientific literature to add precision beyond anthropometry [28, 29, 43]. Further, more investigation of potential mediation and moderation models [20•, 40] will help to advance the understanding of the complex relationship between video game play and obesity via behavioral mechanisms.

There are still many limitations and areas of improvement in this field. A chief limitation is the lack of prospective trials. In the 12 of 26 articles that did report significant associations between video game play and obesity, it is not possible to identify causal relationships. Is video game play causing childhood obesity, or are children with obesity more likely to play video games, or does video game play cluster with other obesogenic behaviors like higher dietary intake and poor sleep and these behaviors may independently explain observed associations? Another limitation of the literature is that video games advance at a much faster speed than study protocols. This lag limits the potential for long-term studies and creates a constantly evolving definition of video games. These challenges may be surmountable with nimble protocol designs and industry-research partnerships [78]. Finally, the objective measurement of video game play has not yet advanced, and research has continually relied on self-report data. Objective measures of television use are possible [79], but video game consoles can also be used for many other purposes (streaming services), video games can be played on multiple platforms (cell phone, console, or computer), and modern video game play varies widely in terms of content (e.g., from first person shooter to dance and sports games to augmented reality in a fantasy world). Therefore, it is increasingly difficult to unobtrusively and objectively quantify children’s video game play.

Conclusions

Overall, there is inconclusive evidence that video games are associated with obesity and, due to the lack of longitudinal studies, virtually no evidence to evaluate if video game play directly contributes to obesity or weight gain in children. On the other hand, there is some (limited) evidence that video game play that involves physical activity can be integrated within behavioral programs to help children to lose weight and attenuate weight gain. Future research should delve into the co-occurrence of video game play with obesogenic behaviors and continue to keep pace with the constantly growing and evolving video game industry to understand the impact of this popular pastime on children’s health.