Television and food advertising: an international health threat to children? (Leading Article).

Obesity is now considered one of the primary child health problems in industrialised countries (1,2). Over the past few decades, obesity rates have increased two to threefold in most developed countries (1,2). As a result of these trends, rates of type 2 diabetes are increasing in youth (3). Studies have also shown that 60% of overweight children have at least one cardiovascular disease risk factor (4). Left unabated obesity may eventually cause as much preventable disease and death as cigarette smoking (5). To ameliorate obesity during childhood, improvements are needed in the dual areas of physical activity and eating behaviours. It is widely agreed that increases in obesity prevalence are related, in part, to changes in the environment that encourage a positive energy balance. These include increases in the availability and marketing of food products, and increased time spent in sedentary activities (6). Thus, macro level influences on obesity risk must be considered in developing interventions to improve weight outcomes. One macro level influence that impacts both eating behaviour and physical activity is the media. Television has been cited as a contributing factor to higher energy intakes (6). Two possible mechanisms have been proposed linking television viewing and obesity:

(1) reduced energy expenditure from excessive television viewing displacing physical activity; and

(2) increased dietary energy intake from eating during viewing or from food advertising (7).

Children view an average of almost three hours of television per day (8,9). Since television is the most widely used advertising medium, it is important to examine exposure to food messages. The study in this issue by Zuppa, Morton and Mehta is important because it documents the types of foods advertised during programs that appeal to children. They found that of the 63 hours of television taped, there were 544 food advertisements; 79% were for non-core foods of the Australian Guide to Healthy Eating. Almost half of the food advertisements were for fast foods and confectionery. Based on this data, children are exposed to one food advertisement on television every seven minutes, and the foods advertised disproportionately promote the consumption of foods high in fat, energy and sugar. As stated in the article by Zuppa and colleagues, Australian children watch an average of 23 hours of television a week. Thus, Australian children are exposed to over 10 000 food advertisements every year. Other content analyses studies (9-12) have shown results similar to the study by Zuppa et al. The majority of studies show that television food advertisements on children's programming target highly sweetened products, and the proportion of advertisements from fast food restaurants is increasing. The study by Zuppa and colleagues, together with other studies, clearly shows that this is an international issue.

Children are being exposed to an increasing and unprecedented barrage of advertisements (13), The principal goal of commercial children's television is to sell products to children, with food and toys being the two most frequently advertised product categories (8). The heavy marketing of high fat foods and food of low nutritional value targetted to children can be viewed as exploitation because young children do not understand that commercials are designed to sell products and do not have the cognitive ability to comprehend or evaluate advertising (8). Numerous studies have documented that children under eight years of age are developmentally unable to understand the intent of advertisements (8,13).

We know that the foods advertised on television are targetted to children across several countries and predominantly for products high in fat, sugar, salt and that these foods are inconsistent with recommendations for good health. However, a critical issue is whether exposure to these food advertisements have any observable effects on children's dietary intake, eating behaviour and weight status. One problem in assessing the impact of television food advertisements is that food advertisements and television are both pervasive and distal, and it is difficult to conduct studies to distinguish effects from confounding variables. Compared to content analyses studies, there have been fewer studies on actual eating behaviour, and most of these studies were conducted in the 1970s and 1980s. The majority of correlational and experimental studies have shown that the amount of time spent viewing television directly correlates with children's food requests, preferences, purchase and consumption of foods advertised on te levision. For example, Taras et al. (14) interviewed 66 mothers of children aged three to eight years, to assess children's viewing habits and children's requests for food advertised on television. The foods that children requested most frequently because they had seen them on television were the foods most frequently advertised on television. Weekly viewing hours correlated significantly with:

(1) reported number of requests by children, and purchases by parents of foods advertised on television; and

(2) children's energy intake; children who watched more television consumed more calories.

These results were similar to those of Galst and White (15) who observed child--mother interaction in the supermarket and then interviewed mothers on their child's television viewing habits. They found that children's television viewing hours correlated with consumption of foods advertised on television and children's attempts to influence their mother's food purchases.

Controlled experimental studies with children have also demonstrated direct effects of exposure to advertising for high energy foods and snack-food choices and consumption. To date, no studies have shown the effect of television food advertising on actual weight status. Increasing amounts of time watching television has been associated with higher intakes of energy, fat, sweet and salty snacks, and carbonated beverages, and lower intakes of fruit and beverages (11). In addition, several large studies have documented associations between number of hours of television watched and the prevalence and incidence of obesity (11). We need the next generation of studies to delve into exposure to television food advertisements and impact on obesity risk and overall dietary intake patterns.

It is evident from the study by Zuppa et al., as well as other studies (9-12), that food advertisements aimed at young children attempt to persuade them to adopt eating patterns contrary to the principles of healthy eating. This is an important public health issue that warrants an international dialogue to discuss ethical concerns and social responsibility towards children, as well as policy, advocacy and education issues and actions to ensure that messages reaching children are in their best interests.

Mary Story, PhD, RD

Professor, Division of Epidemiology and Associate Dean for Student Affairs School of Public Health University of Minnesota Minneapolis, USA

References

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(9.) Consumers International. A spoonful of sugar. Television food advertising aimed at children: an international comparative study. London: Consumers International; 1996.

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(12.) Sustain: The Alliance for Better Food and Farming. TV Dinners: What's being served up by the advertisers. London: Sustain: The Alliance for Better Food and Farming; 2001. p.1-31.

(13.) Strasburger VC. Children and TV advertising: nowhere to run, nowhere to hide. J Dev Behav Pediatr 2001;22:185-7.

(14.) Taras HL, Sallis JF, Patterson TL, Nader PR, Nelson JA. Television's influence on children's diet and physical activity. J Dev Behav Pediatr 1989;10:176-80.

(15.) Galst J, White M. The unhealthy persuader: the reinforcing value of television and children's purchase--influencing attempts at the supermarket. Child Development 1976;47:1089-96.