Following up on my earlier post today on proposal’s to ban junk food ads or promotional characters to kids, take a look at the ACMA’s summary of the scientific evidence on relationships between children advertising and obesity (relevant passage over the fold). It certainly makes me glad that Labor is going to wait until the results of the ACMA Inquiry before committing to its proposal.
The debate about television advertising of food to children exists in a context of concern that obesity is a growing worldwide epidemic (Wadden, Brownell & Foster, 2002). Public health literature points to multi-factorial contributors to obesity, including hereditary, environmental, social and cultural factors. Consideration of the relative role of these complex and interrelated factors to overweight and obesity in children was not in scope for this review, which was of necessity media-focused. However, literature reviews cited that refer to television advertising tend to place children’s exposure to advertising within the framework of effects of television viewing and cite studies of television viewing and obesity (Carter, 2006; Hastings, 2003; Ofcom 2006a).
A number of these studies do establish a correlation between television viewing and obesity in children and adolescents. However, it seems from the research that it is difficult to ‘disentangle’ or isolate television advertising as a factor distinct from television exposure generally (Hastings, 2003; Livingstone, 2006; Ofcom, 2006a). Two points in particular should be noted here:
• where research does establish a correlation between television viewing and obesity, this is reported to be a small or modest relationship, and generally does not provide evidence for causation; and
• studies generally do not distinguish among three possible explanations for the observed association between television exposure and obesity: increased exposure to food advertisements; increased food intake while viewing; or reduced physical activity.
In the UK, the Office of Communications (Ofcom) published a substantial report on obesity, food promotion and advertising that included compilations of data from other sources, a literature review and new data collected for the purpose of the report (Ofcom, 2004). This found a correlation between hours of television viewing and obesity and poor diet, and found television viewing (a very sedentary activity associated with snacking) to be not the only factor, but a consistent contributor. This report also found that television advertising does have an impact on children’s food preferences, but that it is not solely responsible, finding that other factors also affect preferences. In 2006, Ofcom added policy directions to their 2004 research and re-summarised the main findings about obesity and television advertising by stating that ‘television advertising has only a modest direct effect on childhood dietary habits. Other factors in the family home, playground, school dining room and playing fields have a greater role in driving up levels of childhood obesity when compared to the role played by commercial advertising airtime’ (Ofcom, 2006b, Foreword).
Similarly, a wide-ranging overview of the research literature on the relationship between childhood obesity and food advertising on Australian television (Carter, 2006) reported that television food advertising seems to have only a very small, indirect link to childhood obesity,
with the direction of causation and specific contribution of food advertising equivocal. Carter found robust evidence to suggest that television viewing and childhood obesity are related, but qualified that this relationship is weak, with only a small independent effect size. Carter concluded that regulating television advertising, or banning all television, would have little, if any, effect on childhood obesity rates. Livingstone’s 2006 literature review of mainly US and UK research on television advertising and child obesity concluded that there will never be a perfect experiment to establish whether television advertising causes children’s food choice and subsequent diet. (Ofcom 2006a, Annex 9) The following studies exemplify the range of potential variables that may affect the relationship between television exposure and childhood overweight and obesity.