Supplementary file 1_Digital food advertising exposure and perceptions among school-age children: a mixed-methods study in Kazakhstan.docx

BackgroundDigital media expose children and adolescents to frequent food advertising, and this content may influence dietary attitudes and choices. This mixed-methods study examined how school-age children in Karaganda, Kazakhstan, perceived food advertising on YouTube, TikTok, and Instagram, and how exposure patterns varied by age.
MethodsThe study used a three-day diary to record each food advertisement seen on YouTube, TikTok, and Instagram. Diary data were treated as quantitative records and analyzed with ANOVA, Kruskal-Wallis, chi-square tests, and logistic regression. On day one, children completed a semi-structured interview about their viewing habits and reactions to ads. These interviews were analyzed with thematic analysis.
ResultsDiary analysis showed that early adolescents (11–14 years) encountered the most food ads with 14.4 ads/day on average, followed closely by older teens (15–17 years, 13.8 ads/day), whereas younger children (7–10 years) saw far fewer (6 ads/day). TikTok was the dominant source for food ads exposure with Instagram second and YouTube the least. By product, sweetened beverages and fast foods were the most frequently advertised categories. Exposure did not differ overall between morning and evening sessions (p = 0.06). Diary entries showed that older adolescents aged 15–17 years reported greater purchase autonomy compared to younger children. Thematic analysis of interviews identified that younger children found advertisements entertaining, 11–14-year-olds reported mixed responses including irritation, and older adolescents displayed critical awareness, often dismissing advertisements as repetitive.
ConclusionSocial media food advertising is pervasive among Kazakhstani children, especially early adolescents. TikTok and Instagram feed flows dominated young viewers’ exposure, with high-calorie products (sugary drinks, fast foods, energy drinks) highly featured. Younger children tended to enjoy ads, whereas older teens generally discounted them, yet older teens’ higher autonomy and consistent exposure to enticing ads suggest potential influence on their choices. Strengthening media literacy and critical thinking among school-aged children should become an important direction in public health to reduce the influence of digital marketing on food-related behavioral decisions.