Doctor of Philosophy
Background A growing body of evidence indicates that unhealthy food marketing exposure affects children’s food attitudes, preferences and consumption, most likely through a logical, cumulative sequence of cognitive and behavioural responses. An important reason impeding policy change to restrict food marketing to children is the lack of evidence showing a direct link between food marketing and children’s energy intake and the sustained effect of exposures on children’s body weight. In experimental studies, children’s food intake is the most relevant outcome measure to investigate this direct link.
Brief exposure to food advertising on television (TV) or online advergames (branded games) has an immediate direct effect on children’s food consumption, significantly increasing their intake of snack foods, but whether or not this increased energy intake is compensated for at later eating occasions is not known. Many of these single exposure experimental studies have been conducted in laboratory settings and have not accounted for the cumulative effects of media exposures or the impact of repeated exposures across multiple media.
Aim The research outlined in this thesis aimed to investigate the direct effects of sustained exposure to unhealthy food advertising on TV and online advergames on children’s dietary intake and its potential influence on children’s weight. Furthermore the research aimed to determine whether there was an increased effect of advertising among children with overweight and obesity and/or children whose parents reported controlling feeding practices; and to investigate how the creative content within the advertisements affected children’s recognition and attitudinal responses to advertised food brands.
Methods A within-subject, randomised, crossover, counter-balanced trial was conducted across four, six-day school holiday camps in New South Wales, Australia (n=160, aged 7–12 years). Two gender- and age-balanced groups were formed for each camp (n=20), randomised to either a multiple media or single media condition and exposed to food and non-food advertising in an online game and/or a TV cartoon. Children’s food consumption (kilojoules (kJ)) was measured at a snack immediately after exposure and then at lunch later in the day. To isolate the effects of advertising, international food brands, not available for sale in Australia or advertised on Australian commercial TV stations, were used. Children completed a brand recognition and attitude survey pre- and post-intervention. Parents completed the Child Feeding Questionnaire at baseline. Marketing techniques and themes in individual TV food advertisements and advergames were analysed and described.
Findings One hundred and fifty four children completed the study. All children in the multiple media condition ate more at a snack after exposure to food advertising compared with non-food advertising; this was not compensated for at lunch, leading to additional daily food intake of 194 kJ (95% CI 80–308, p=0.001). Exposure to multiple media food advertising compared with a single media source increased the effect on snack intake by a difference of 182 kJ (95% CI 46–317, p=0.009). Food advertising had an increased effect among children with heavier weight status, and among children whose parents reported controlling feeding practices, in both media groups.
There was a significant increase in the recognition of all food brands post-exposure. All brands were rated positively. The majority of brands appealed to children of all ages, with children wanting to eat the advertised products. Playing the online advergame appeared to enhance children’s opinions of a person who would eat the promoted brand, with the highest ratings for positive consumer perceptions by children in the TV and advergame group. Furthermore, brand consumers were rated as more cool by children who played the advergame compared with those saw the TV advertisement only. Common persuasive techniques used across the TV advertisements included brand equity characters, fantasy, happiness and highly palatable food products; techniques unique to the most recognised and highly rated TV advertisements included anti-adult themes, humour, parent-pleasing and parental-themes.
Significance and contribution to knowledge Online advertising combined with TV advertising exerted a stronger influence on children’s food consumption than TV advertising alone. The lack of compensation at lunch for children’s increased snack intake after food advertising exposure indicates that unhealthy food advertising exposure contributes to a positive energy-gap, of a magnitude that would cumulatively lead to the development of childhood overweight. To our knowledge this is the first experimental study to demonstrate a direct link between children’s exposure to food advertising and their dietary intakes, beyond measuring a snack consumed at the time or immediately after the advertising exposure. The increased effects observed in children with a heavier weight status and whose parents reported controlling feeding practices highlights two groups of children with particular vulnerability. Of significance, however, is that all children in the multiple media condition were affected by the food advertising, regardless of their self-regulatory capacity. Given that the multiple media group in this study most closely emulates young people’s current media experiences, these findings are of particular concern.
The persuasive techniques within the study advertisements delivered a marketer’s objective of building brand-equity by stimulating children’s brand recognition and positive affect. Yet these techniques are not excluded under current regulatory schemes in Australia.
The findings reported in this thesis clearly highlight the need for stricter regulation on the extent and power of food marketing to children and call for a review of current regulatory arrangements. This research adds a significant contribution to the evidence supporting the need for legislation to limit unhealthy food marketing across multiple media platforms to help protect children.
Norman, Jennifer Anne, Sustained Impact of Unhealthy Food Advertising on Children’s Dietary Intake, Doctor of Philosophy thesis, Early Start, University of Wollongong, 2018. https://ro.uow.edu.au/theses1/463
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.