Exploratory analysis of a cluster randomized controlled trial of a multi-strategy intervention delivered via online canteens on improving the nutritional quality of primary school students’ pre-ordered foods & drinks at recess

School canteens are a recommended setting to deliver public health nutrition strategies given their wide reach, and frequent use by children. Online canteens, where users (i.e. students or their carers) pre-order and pay for food and drinks online, represent attractive systems to deliver strategies that encourage healthier food choices. There have been few studies exploring the efficacy of public health nutrition interventions in online food ordering environments. Therefore, this study aims to assess the efficacy of a multi-strategy intervention implemented in an online school canteen ordering system in reducing the energy, saturated fat, sugar, and sodium content of students’ online recess orders (i.e. foods ordered during the mid-morning or afternoon snack period). This was an exploratory analysis of recess purchases for a cluster randomized controlled trial that initially sought to examine the efficacy of the intervention on lunch orders. A total of 314 students from 5 schools received the multi-strategy intervention (involving menu labelling, placement, prompting and availability) that was integrated into the online ordering system, and 171 students from 3 schools received the control (usual online ordering). Analysis of main outcomes found that the mean energy (difference: −269.3 kJ; P = 0.006), saturated fat (difference: −1.1 g; P = 0.011) and sodium (difference: −128.6 mg; P = 0.014) content per student recess order was significantly lower in the intervention group than the control group at 2-month follow-up. Findings suggest that embedding strategies to encourage healthier choices within online canteen ordering systems can improve the nutrient composition of student recess purchases. These results add to the current evidence base suggesting that interventions delivered via online food ordering systems represent an effective strategy for improving child public health nutrition in schools.