Cluster randomised controlled trial of a consumer behaviour intervention to improve healthy food purchases from online canteens: study protocol

Introduction: School canteens represent an opportune setting in which to deliver public health nutrition strategies given their wide reach, and frequent use by children. Online school canteen ordering systems, where students order and pay for their lunch online, provide an avenue to improve healthy canteen purchases through the application of consumer behaviour strategies that impact on purchasing decisions. The aim of this study is to assess the efficacy of a consumer behaviour intervention implemented in an online school canteen ordering system in reducing the kilojoule, saturated fat, sugar and sodium content of primary student lunch orders. Methods and analysis: The study will employ a cluster randomised controlled trial design. Approximately 1040 students (aged 5–12 years) from 10 primary schools in New South Wales, Australia, currently using an online canteen ordering system will be invited to participate. Schools will be randomised in a 1:1 ratio to receive either the intervention (enhanced system) or control (standard online ordering only). The intervention will include evidence-based strategies shown to influence healthy food purchasing (strategies targeting availability, menu labelling, placement and prompting). The primary outcomes of the trial will be the mean content per student online lunch order of (1) energy (kJ), (2) saturated fat (g), (3) sugar (g) and (4) sodium (mg). The impact of the intervention will be determined by between-group assessment of the nutritional content of lunch purchases over a 2-month period postintervention initiation. Ethics and dissemination: The study was approved by the Hunter New England Human Research Ethics Committee, University of Newcastle Human Research Ethics Committee and New South Wales Department of Education and School Communities. Study findings will be disseminated widely through peer-reviewed publications and relevant presentations in international conferences and to stakeholders. Trial registration number: ACTRN12616000499482.