current evidence indicates that the explanatory variables at hand, including exposure to television advertising, altogether do not account for a substantial amount of the variability in juvenile adiposity.

Given that exposure to television advertising is just one of the likely influences on adiposity that is included in these analyses, if this exposure has a direct causal and independent influence on adiposity, it will be smaller still than the influence of all variables together. In fact, those studies that have provided estimates of that influence suggest that it would be small. For example, Storey et al. (2003) estimated that for every additional hour of daily television viewing, children’s and teens’ BMI could increase by about 0.2, and Dietz and Gortmaker (1985) estimated that the prevalence of teenage obesity could increase by about 2 percent of teens. Although any causal influence of television advertising on adiposity is likely to be very small, it is not necessarily inconsequential. In a national population of about 75 million young people under age 18 years (U.S. Census Bureau, 2005), 2 percent is 1.5 million young people. With these factors in mind, if exposure to television advertising directly influences childhood adiposity, the influence would be consequential when aggregated over the entire population of American children and teens.

In summary, as was the case when examining the influence of marketing on precursors of diet and on diet itself, most of the research relevant to marketing’s influence on diet-related health is about the effects of television advertising of foods and beverages. The one diet-related health outcome that has been studied to any degree is adiposity. Most of the research about television advertising and adiposity has not focused explicitly on exposure to television advertising as the causal variable, but it is amenable to use for the committee’s purposes because it measures television viewing, which is well correlated with exposure to television advertising (Chapter 4).

Finding: The association between adiposity and exposure to television advertising remains after taking alternative explanations into account, but the research does not convincingly rule out other possible explanations for the association; therefore, current evidence is not sufficient to arrive at any finding about a causal relationship from television advertising to adiposity among children and youth. It is important to note that even a small influence, aggregated over the entire population of American children and youth, would be consequential in impact.

This finding is based entirely on the available research that permits examination of the relationship between exposure to television advertising and adiposity. When this research is considered in the context of the research reviewed earlier on the relationship of television advertising to precursors of diet and to diet itself, there is some basis for concluding that



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