School-based behaviour change intervention to reduce ultra-processed food consumption among adolescents: evidence from a cluster-randomised controlled trial in India.

backgroundThe global surge in ultra-processed food (UPF) consumption is a major public health challenge, particularly among adolescents. UPFs, characterised by high energy density, added sugars, fats and sodium, and low essential nutrients, are linked to poor diet quality and heightened risks of obesity, diabetes and all-cause mortality. Despite growing concerns, there is limited evidence on school-based interventions targeting UPF reduction in low- and middle-income countries (LMICs) like India.

methodsA cluster-randomised controlled trial was conducted across 12 public schools in Chandigarh, India, targeting Grade 8 adolescents and their parents. The intervention was structured around the PRECEDE-PROCEED (Predisposing, Reinforcing, and Enabling Constructs in Educational Diagnosis and Evaluation-Policy, Regulatory, and Organizational Constructs in Educational and Environmental Development) Model and comprised 11 sessions for adolescents delivered over 6 months. Additionally, a single educational session was conducted for parents to enhance their awareness of reducing UPF consumption and encouraging healthier dietary behaviours. Dietary intake data were collected at baseline and endline using two non-consecutive 24-hour dietary recalls. Foods were categorised into four groups based on the extent and purpose of industrial processing using NOVA food classification. Energy levels were estimated using Prospective Urban Rural Epidemiology (PURE) study data. The intervention's effectiveness was evaluated using a difference-in-difference (DiD) analytical approach.

findingsThe intervention significantly reduced UPF energy intake among adolescents by 1062 Kcal/day (95% CI -2100 to -67) and processed food by 274 Kcal/day (95% CI -526 to -23). However, no significant changes were observed in minimally processed food consumption. Among parents, the intervention had no significant impact on energy intake for any of the NOVA classified food categories. Process evaluation highlighted high participant engagement and feasibility of the intervention in school settings.

conclusionThis study demonstrates the potential of school-based behavioural interventions to reduce UPF consumption among Indian adolescents, addressing a critical gap in public health research and practice in LMICs. TRIAL REGISTRATION NUMBER: CTRI/2019/09/021452.