Social media use and associated food-related habits among Kenyan teenagers: a cross-sectional study of digital influence on public health nutrition

Social media use is increasingly influencing lifestyle choices and, notably, dietary choices and food-related practices of teenagers. This study aimed to determine the extent and nature of social media use and its associated food-related habits among teenagers in Kenya. The study employed a cross-sectional study design incorporating both quantitative and qualitative techniques. The study was conducted in the metropolitan area of Mulolongo, Machakos County, Kenya. Using proportionate and simple random techniques, the study sampled 357 teenagers, 13–19 years old. The study utilized structured questionnaires administered in face-to-face interviews, alongside focus group discussions for data collection. Qualitative data were analyzed using thematic analysis, while quantitative data were analyzed using descriptive, bivariate, and multivariate logistic regression analysis. Findings revealed that (72.5%) of teenagers use social media, averaging 2.65 ± 0.13 hours on weekdays and 3.08 ± 0.14 hours on weekends on social media, with WhatsApp, Instagram, and TikTok being the most frequently used platforms. Usage patterns showed a statistically significant gender difference, p < 0.05. Social media was rarely used to seek health or nutritional information (0.8%). While on social media (34.5%) of teenagers watch food-related videos, (32.8%) snack while browsing and (54.3%), reported exposure to food advertisements, with fast food ads being the most common. Notably, access to WhatsApp (Crude O.R. = 4.41, 95% CI: 1.57–12.39, p < 0.001) and Instagram (Crude O.R. = 4.22, 95% CI: 1.18–15.08, p = 0.02) was associated with higher odds of being underweight, while exposure to food advertisements was associated with both underweight (Crude O.R. = 0.48, 95% CI: 1.22–2.05, p = 0.04) and overweight risks (Adjusted O.R. = 4.4, 95% CI: 1.90–21.73, p = 0.04). Qualitative insights substantiated quantitative findings, asserting that participants’ food choices were influenced by aspirational consumption patterns linked to online trends, habitual snacking during digital engagement, and intensified exposure to food-related advertisements and promotions, particularly for fast foods and snacks, across social media platforms. Social media use among teenagers is linked to both underweight and overweight status. The pervasive influence of food advertising, specifically energy-dense, nutrient-deficient food, shapes unhealthy practices, while limited exposure to credible health content signals a missed opportunity. Public health action should focus on regulating online food advertisements and leveraging social media for nutrition education, and strengthening teenagers’ digital literacy to advance healthy eating behaviors.