Overall, the identified studies present a strong, comprehensive body of evidence demonstrating the powerful influence of food marketing exposure. The studies also identify the influences on children’s attitudes, preferences and consumption of the vehicles of promotion and associated techniques, particularly with regard to television commercials, and the marketing techniques used in packaging of products. The review signposts the vehicles of promotion and marketing techniques that require further assessment and the importance of further research to strengthen the current body of evidence.
A lack of evidence linking food marketing to childhood obesity is an oft-cited reason, by both governments [101
] and the food industry [103
], for the limited action to restrict children’s exposure to unhealthy food marketing. This review of the body of evidence indicates otherwise. It has documented a strong link between food marketing to childhood obesity. The findings of this review support further restriction of food marketing to children as a key solution for the management of childhood obesity [21
4.2. Priority Areas Identified for Future Research
This review identified areas of future research to strengthen the body of evidence. These consisted of additional methodology and additional marketing techniques which are detailed in Table 2
Marketing communications aim to influence children’s thoughts and behaviours via both the implicit and explicit memory; thus, some messages are consciously recognised when processed, and some are processed automatically without conscious awareness. Therefore, for researchers seeking to quantify the behavioural impact of marketing, it is crucial that the methodology used be appropriate to the type of exposure assessed and the relevant measurable outcome. For example, for overt marketing, it may be most appropriate to capture explicit articulation or attitude ratings, but with covert marketing exposure, it may be beneficial to observe physiological behavioural responses. This is especially relevant as studies noted an increasing use of marketing techniques designed to influence children’s implicit memory [105
]. Research into these implicit and physiological responses is extremely valuable for expanding knowledge about the individual and automatic responses food marketing can prompt. Research with children, who may have more difficulty expressing themselves than adults [107
], requires appropriate methodology and the use of a range of implicit and explicit techniques to ensure findings are not reliant on the children explicitly expressing their reaction. Such studies are vital for attaining a holistic understanding of the impact of food marketing on children. In this review, very few studies implemented a physiological measure to evaluate the implicit influence of food marketing. This is a notable gap in the available evidence.
It is also necessary, particularly when conducting research with children, to explore motivations and reasoning through means other than experimental studies, for example, with the use of qualitative studies. Qualitative and child-centred methodology can help children to feel meaningfully involved [109
] and may allow researchers to tease apart what specific aspects of marketing resonate most with children. This review only identified three studies that used qualitative methodology. Future research incorporating more qualitative research will add greater insight and weight to the body of evidence.
In all studies, researchers had deemed the exposure stimuli as potentially appealing to children. The materials were often popular global or national brands children were likely to have seen before. This highlights an opportunity for future research. Firstly, children have been described as ‘experts in their own lives’ [110
] and may be the most accurate source for determining appropriate stimuli, especially for studies that seek to measure the impact of exposure so as to contribute to policy evidence at a global level. This is not to say the studies made a mistake in choosing the stimuli, but more studies should champion the use of stimuli informed by the participants, in turn using brands and products considered most relevant to their participants. Secondly, a majority of studies used brands assumed popular with and recognisable by with children. Using unfamiliar brands ensures measurement of exposure outcomes occurs in the absence of existing brand associations and preferences. Future research should also seek to use unfamiliar or mock food brands as stimuli.
Furthermore, future research should measure the impacts of accumulative exposure, reflective of the longer-term effects of food marketing and children’s exposure to repeated promotions in real life. Two studies in this review investigated whether or not children compensate for advertising-induced snack consumption at subsequent meals [52
]. The results identified potential links between advertising and longer-term body weight and health outcomes, evidence vital for informing global policymaking.
Additional marketing techniques for future research foci are of a contemporaneous nature, which likely explains why new media appear to be an understudied area of food marketing. Content analyses examining digital platforms have discovered a vast amount of marketing on popular children’s websites [111
] and food brand websites [112
]. However, this review identified very few studies explored the effect of marketing on websites or other digital platforms. The studies exploring social media and internet advertisements found these forms of marketing to children had detrimental consequences for dietary health, and this warrants further research. This is not without methodological and ethical challenges that make identifying and replicating what children are exposed to online a hurdle to overcome [114
], yet the evidence generated is imperative for informing contemporary global policymaking.
Further to a need for more research into the digital environment, there was a bias identified in the approach studies used to measure the influence of online games, as all studies implemented an advergame model. Advergames are very common [115
] and are very influential on children, if not more influential than television commercials when compared on the same participants [34
]. Therefore, understanding and recognising their influence is vital. However, children are not thought to spend much of their online time on food brand websites where advergames are housed [116
]. It is believed “gaming” as an online phenomenon is on the rise [117
], and the games children play contain numerous contemporary advertising techniques, such as pop-up and unlock-to-play advertisements [118
]. Future research should seek to explore these techniques and establish their impacts, to ensure academic knowledge synchronises with the contemporary marketing environment.