Identifying food marketing to teenagers: a scoping review

Background Teenagers are aggressively targeted by food marketing messages (primarily for unhealthy foods) and susceptible to this messaging due to developmental vulnerabilities and peer-group influence. Yet limited research exists on the exposure and power of food marketing specifically to teenage populations. Research studies often collapse “teenagers” under the umbrella of children or do not recognize the uniqueness of teen-targeted appeals. Child- and teen-targeted marketing strategies are not the same, and this study aims to advance understanding of teen-targeted food marketing by identifying the teen-specific promotion platforms, techniques and indicators detailed in existing literature. Methods A systematic scoping review collected all available literature on food marketing/advertising with the term “teenager” or “adolescent” from nine databases, as well as Google Scholar for grey literature, and a hand search of relevant institutional websites. Included were all peer-reviewed journal articles, book chapters, and grey literature in which food marketing to youth was the central topic of the article, of any study type (i.e., original research, reviews, commentaries and reports), and including any part of the 12–17 age range. Results The 122 articles reviewed define the scope of existing literature on food marketing to young people age 17 and under, identifying leading trends in countries studied (United States, 52%), populations identified (children and teens studied concurrently, 36%), outcomes measured (advertising exposure, 54%), study type (cross-sectional, 58%) and methods used (content analysis, 46%). The promotion platforms and techniques used by food marketers to appeal to young people (as reported in the literature) are also identified and classified. Few studies (7%) use indicators to identify teen-targeted food marketing. Conclusions Unique treatments of teen populations are limited in food marketing literature, as is the application of clear indicators to identify and differentiate teen-targeted food marketing from child- or adult-targeted content. Given the need to better measure the presence and power of teen food marketing, this is a significant oversight in existing literature. The indicators identified will help researchers to develop more accurate strategies for researching and monitoring teen-targeted food promotion.


Background
Regulations limiting food marketing often focus on children under age 13, despite the fact that teenagers are also susceptible to food marketing appeals [1]. Teenage vulnerability to food marketing, and especially digital promotions, stem from unique developmental factors (i.e. cognitive and emotional) [2,3], peer-group influence [4,5], and high levels of exposure to advertising messages [1,[6][7][8][9][10]. Yet research on the impact of food marketing to teenagers is limited [7,[10][11][12]. Teenagers, moreover, are often assessed as part of the broader category of children instead of as a unique population [11]. In fact, very few studies define or provide criteria to identify teen targeted food marketing. This scoping review examines existing studies on food marketing/advertising involving teenage populations (ages [12][13][14][15][16][17] in order to identify the scope of current research, including age ranges, outcomes, promotion platforms, techniques, and indicators. Specifically, the identification of indicators will provide a firm set of criteria for measuring the presence and power of teen-targeted food marketing. Determining how to better identify teen-specific marketing appeals will allow for the monitoring of exposure and message content in order to inform regulatory policies on food marketing to teenagers. While many studies examine child-specific food marketing content (for example, the use of cartoon characters and 'fun' appeals [13][14][15][16][17][18][19][20][21][22][23][24]), little research isolates and identifies teen appeals. This is significant for teenage health since teenagers may be targeted more heavily by food marketers who are prohibited from appealing to children; it is also relevant to children, who may be attracted to teen-targeted content (WHO, 2018). Globally many countries recognize the deleterious effects of food promotion on children's health, and have restricted or prohibited the marketing of unhealthy foods [7,25]. Canada is also aiming to restrict food marketing to children under Bill S-228, the Child Health Protection Act, which is currently awaiting approval by the Senate [26]. However, such restrictions do not apply to teenagers, even though teenagers are influenced by marketing appeals. Indeed, teenagers' awareness of, or cynicism towards, advertising messages does not necessarily make them more critical consumers or less persuaded by advertising [7,11]. In light of the need for expanded knowledge around teen food marketing, this review is guided by the following research questions: 1) how do existing studies identify teenage populations (i.e., age range, collapsed into child populations, etc.)?; 2) how is teen-targeted food marketing identified and measured?; 3) what promotional platforms and techniques are examined?; and 4) what criteria or 'indicators' are used to isolate teen-specific appeals?

Literature search
A systematic search of all available English language literature (all dates up to July 2018) was conducted using the following search terms: (teenager OR adolescent) AND "food marketing"; (teenager OR adolescent) AND "food advertising". Databases used included Scopus, Web of Science, Embase, Medline, JSTOR, CAB Abstracts, CINHAL, and PubMed. Google Scholar was used to locate grey literature: the first 800 entries in the search return list were scanned, as per the recommended protocol for topic searches, which identifies saturation at page 80 [27]. A hand search was also conducted of the websites for the World Health Organization (WHO), the Federal Trade Commission (FTC), and the Institute of Medicine (IOM). Figure 1 outlines the search strategy.

Inclusion criteria
All peer-reviewed journal articles, book chapters, and grey literature examining food marketing to youth as the central topic were included, along with any study in which any individual in the age 12-17 range appeared (whether labelled as 'teenager' or overlapping with/collapsed into 'child' or 'adult' categories). Included were all study types (including original research, reviews, commentaries and reports) and all food promotion platforms and techniques. Excluded were studies that examined whole foods (as opposed to packaged/processed food), alcohol advertising, parental opinions about food marketing to teenagers, and general screen time exposure (compared to screen time for food marketing). Also excluded were studies examining unhealthy products marketed to children where food is only one category of products (i.e., food, cigarettes, alcohol), as well as studies where food advertising is only one of multiple factors being examined as a determinant of health (e.g., alongside physical activity, nutritional value of foods, etc.). Finally, studies were excluded if they examined mass media effects on children's attitudes and behaviours where food advertising is only one of multiple topics (e.g., alongside issues of body image or tobacco smoking).

Data extraction and analysis
Abstracts were reviewed for selection by one author and two graduate students. The team extracted data for the following: study aims/objectives, study type, methods, population, food promotion platform and/or technique, country studied, and indicators of "teen-targeted" food promotion. Specifically, population was recorded in terms of both defined age range (i.e., [12][13][14][15][16][17] and/or label used for age group (i.e., teenager, adolescent, child, adult). Food promotion platform was defined as the communication channel, format or setting used to reach teenagers. Examples of platforms include television, social media, and convenience stores. Food promotion techniques was defined as the specific strategies or practices used to promote food brand or product awareness to teenagers. Examples of techniques include engagement tactics (i.e., viral marketing, info mining), and publicity tactics (i.e., philanthropic marketing, event sponsorship, etc.). Indicators refer to the criteria describing specific appeals in food marketing messages. Examples of indicators include characters or spokespersons, and themes. For the analysis, we reviewed and coded the following data categories: aims/objectives to isolate measured outcomes; population to identify variations in age ranges/labels used; food promotion platform and technique to categorize research focus; and indicators to identify common themes/categories in food marketing content.

Outcomes and study approaches
The majority of outcomes measured belong to the category of advertising/media exposure (54%), with much smaller numbers of studies identified in relation to behaviours (13%), attitudes (11%), obesity (7%). Nineteen percent of the studies were reviews, reports and commentaries without measurable outcomes. In terms of study type, the majority of studies are cross-sectional (58%), while content analysis is the most frequently used method (46%).

Teen-specific marketing appeals
Of the 122 included studies, only 9 specified criteria, or indicators, to identify defining aspects of teen-targeted food marketing. Collectively, they offer a list of 42 indicators that describe the content of teen food advertising from characters and celebrities, to actors/models, to themes and activities. These studies and their indicators are reported in Table 1.
The indicators reported in Table 1 were then summarized into 12 categories to represent different aspects of marketing content targeting teens. These indicator categories are: teen actors, teen themes, teen media, teen products, teen incentives, celebrities that appeal to teens, teen activities, animated characters, teen language, "fun", teen humour, and teen music. The reported frequencies of these categories across the studies identified are represented in Fig. 2. As illustrated, a wide variety of indicators are in use across a small number of studies (7%), while the vast majority of literature uses no indicators at all to identify teen-specific food marketing content (93%).

Discussion
This study highlights that there are very few food marketing studies that focus exclusively on teenage populations, despite this group being highly targeted and vulnerable to promotional appeals [1,7,11]. The problem with examining teens alongside, or as part of the larger group of, child populations is that teen-specific marketing appeals are rarely differentiated from childfocused ones. This presents challenges in terms of identifying and accurately measuring the presence of teen food promotion. Indeed, in existing literature, such content is often passively identified by selecting a promotional platform that targets teenagers (e.g., a television channel), and then performing a content analysis of its advertisements. In such studies, the main outcome being measured is exposure level to food marketing (i.e., number of commercials within a given time frame), with limited attention to the actual content of those messages.
The assumption is that, based on the platform, the advertisements will by default appeal to teenagers.
As this scoping review reveals, television advertising remains the primary focus of literature on youth food marketing: 40% of the included studies focus exclusively on television programming, and 66% overall include television as an object of study (as the main focus, or in addition to other platforms). This emphasis on television in existing food marketing studies on youth means that other platforms (e.g.., digital, settings-based), which represent important sources of teen-targeted messaging, are less understood. Indeed, the World Health Organization has identified regulatory focus on broadcast advertising as a key challenge to implementing policy on food marketing to young people because it ignores the digital sphere (as well as sponsorship and product packaging) [7]. Settings-based marketing also requires more attention: a recent scoping review found that exposure levels for children under age 17 in Canada are potentially underestimated, as they are marketed to in their homes, schools, and supermarkets [10].
The existing focus on television programming also excludes the range of promotion techniques now used to market food and beverages to youth [3]. We define promotion techniques as specific strategies used to promote brand awareness to youth, as opposed to promotion platforms which are the communication channels used to reach them. In the literature identified, promotion platforms and techniques were often conflated. This is problematic because the former is simply a delivery mechanism, while the latter is a targeted strategy or practice. Stated differently, food marketing platforms can be used to measure exposure to advertising, but the power of that advertising is more accurately assessed by examining the content of promotion techniques [145]. This study identified a remarkable variety of promotion techniques in use to target young people (17 and under): 78 unique items were grouped into the ten categories (described in the results section), ranging from settings-based and digital tactics, to more traditional approaches such as brand familiarity and sponsorship/endorsements. When it comes to teen food marketing, promotion techniques are significant as teenagers may be targeted by specialized techniques that do not reach younger children. For example, consider information gathering/info mining or incentives that are the result of signing up for subscriptions or accounts for registered users over the age of 13; point-of-purchase displays in stores where teenagers use their own spending money; viral marketing and/or word-ofmouth marketing (which may be significant due to the importance of peer acceptance), and the social/symbolic value of food (brands, or 'cool' food products) within the peer group [146,147]. However, the content of these targeted messages, not simply the type of strategy, matters as well. It is critical to identify marketing content that appeals to teens in order to better understand its potential impacts. For instance, when it comes to "special offer" promotions, are teens incentivized by coupons or by limited-edition products? Which tactic is more likely to influence their food preferences and/or motivate their purchase behaviours? The need for improved understanding of the content of teen-targeted food marketing is particularly acute in the Canadian context, where Health Canada is preparing to implement Bill S-228, the Child Health Protection Act, which will prohibit the marketing of unhealthy food and beverages to children under age 13 [26]. As part of this initiative, Health Canada has committed to monitor the marketing of unhealthy foods to teenagers aged 13-17, in order to assess whether food and beverage marketing to teenagers will increase post-legislation. Additionally, the World Health Organization has identified the need for worldwide monitoring of digital marketing to children under 17, in light of the increasing popularity of social media/mobile devices for this age group which involves targeted/personalized advertising [148]. Monitoring depends not only upon the ability to accurately identify where and when food marketing reaches teens, but also how it appeals to them, and the use of indicators is critical to this process. The indicators identified in this study are a good starting point for considering how teen-targeted marketing appeals are specific to that age group. However, some indicators are clearer than others for determining inclusion/exclusion. For example, the presence of a teenaged actor or animated character counts as teen-targeted, as does language that directly addresses the teen audience (i.e., the terms "teen", "teenager", "adolescent"). These are straightforward to identify. The following categories are less clear: teen theme, teen activity, celebrities that appeal to teens, teen incentives, teen humour, and teen music. Specific definitions are needed for each of these categories so that the interpretation of these terms is not reliant on the subjective opinions of researchers or policy makers. Finally, several of the indicators identified in existing literature are completely unclear as inclusion criteria: does the category of "media" refer to the platform used to reach teens, or the use of teen media as a theme (i.e., image of a smartphone in the advertising)?; does "product" refer to ones made-for-teens, or to any products that teens find appealing?; and where the indicator "fun" refers to a product and its representation in advertisements, is this characteristic valued by teen audiences, or are they perhaps more concerned with "cool/ trendy"? Additional qualitative research is needed to determine how teens themselves describe and define food marketing directed at them, in order to properly differentiate between teen-specific, child, and adult oriented content, and to inform conceptions of teen indicators.
It is important to note a limitation of this review: the summary of indicators is based on a small number of identified studies, and their validity needs to be tested in future research. Studies that focus exclusively on the 12-17 year old age range are needed in order to examine the uniqueness of teen appeals. Nuanced research in this area will provide much needed insight into the power of teenager-targeted food marketing, and its potential impacts on food attitudes and behaviours.

Conclusions
Food and beverage marketing to teenagers is ubiquitous. However, little focused research exists on teenage populations, despite their vulnerability. The most commonly measured outcome in studies of food marketing to young people (17 and under) is exposure to advertising-and most often in television programming-which ignores the increasing range of promotion platforms and techniques specifically targeting teenagers. More research is needed to identify teen-specific food marketing content, and this scoping review is the first to analyze the specific indicators currently being used for evaluating such appeals. The ability to isolate teen-targeted food and beverage marketing will allow for more effective monitoring of its presence, and assessment of its power and potential impacts on teenagers, in order to inform policy around its regulation.
Acknowledgements CE would like to acknowledge funding support from the Canada Research Chair Program.
Authors' contributions CE conceived and designed the study. ET carried out the study, including data collection and analysis. ET drafted the manuscript. CE reviewed the manuscript and provided feedback and edits. Both authors reviewed and approved the final content.

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