Associations of school food environment characteristics (availability, pricing, and marketing) with adolescents’ dietary intake and anthropometric outcomes

The rising prevalence of childhood obesity is a major public health concern, partly driven by obesogenic food environments. This study examined school food environment characteristics and their associations with dietary intake and anthropometric indicators among students in Shiraz, Iran. In this cross-sectional study, food environments of school canteens (SCs) and surrounding food retail outlets (FROs) were assessed in 24 upper secondary schools using a validated food retail environment assessment protocol. Dietary intake was assessed in 656 students using a validated 90-item Food Frequency Questionnaire, and anthropometric measurements were collected concurrently. A total of 100 FROs and 24 SCs were assessed. Unhealthy foods accounted for 70.93% of food-related shelf space in FROs and 87.09% in SCs. Price differences varied across food groups, with unhealthy products being more expensive in some categories and less expensive in others. Overall, 530 food advertisements were identified (499 in FROs and 31 in SCs); according to the WHO-EMR-P model, 90.8% of advertisements in FROs and 100% in SCs were classified as non-permissible. In mixed-effects models, greater availability of each food category was associated with higher intake of the corresponding food category, including healthy dairy products (B = 3.291, P = 0.008), unhealthy dairy products (B = 6.737, P = 0.042), unhealthy cakes and biscuits (B = 1.428, P = 0.002), beverages (B = 0.403, P = 0.048), chips and puffs (B = 0.090, P = 0.023), and sweets (B = 0.175, P = 0.042). Food prices were not significantly associated with dietary intake. Higher advertising density was associated with healthy ready-to-eat foods (B = 0.711, P = 0.049) and simple sugars (B = 3.054, P = 0.015). No school-level food environment indicator was associated with overall nutritional intake or anthropometric outcomes. School food environments in Shiraz were characterized by a predominance of unhealthy foods and widespread unhealthy food advertising. Food availability showed the most consistent associations with food-group-specific intake, whereas price and advertising showed more limited associations. Strengthening and monitoring food environment policies in and around schools may help improve the availability and promotion of healthier food options.