The short-term effects of television advertisements of cariogenic foods on children's dietary choices.

Objective: To investigate the short-term influence of the advertising of cariogenic foods on children's dietary preferences, and the possible moderating effect of several factors on this influence.

Methods: One-hundred and eighty-three children, 11-12 years of age, were exposed to advertisements showing sugary food and non-food items, in a within-subject counterbalanced design. Their preferences for unhealthy and healthy foods, and their ability to recall or recognise the advertisements, were measured following both sessions. Information on their dietary habits, leisure activities and sociodemographic details were obtained through a questionnaire completed by their parents. Their decayed, missing and filled teeth (DMFT) index, body weight and height were also recorded. A generalised linear mixed model was used to examine the differences in food preferences between experimental conditions, and the associations between children's preferences and the other factors assessed.

Results: Exposure to food advertisements significantly decreased the selection of healthy foods. Children with a higher DMFT index chose a higher percentage of unhealthy foods, and children who spent more time watching television chose an increased number of healthy foods, after their exposure to food advertisements. Regardless of condition, girls selected fewer foods than boys. Children with a higher DMFT index selected more unhealthy foods than children with a lower DMFT index. Obese children chose an increased number of healthy foods than those who were overweight and normal weight.

Conclusions: Food advertisements can divert, for a short time, children's preference over healthy food choices, and could lead to changes in their eating habits, which may put them at higher risk of dental diseases and obesity.