Can an app-based intervention targeting parents, with or without additional support, improve the nutritional quality of foods and drinks packed in lunchboxes of primary school aged children.

A cluster randomised trial design will be utilised to test the efficacy of an app only intervention (low dose) in comparison to an app plus school guidelines, classroom curriculum and physical resource (full dose) intervention in improving the nutritional quality of foods and drinks packed in the lunchbox. The lunchbox program aims to improve the contents of children’s lunchboxes by supporting parents/carers to swap what is packed from discretionary (“sometimes”) foods and drinks to core (“everyday”) foods and drinks. The program seeks to address the barriers faced by parents to packing a healthy lunchbox (time/convenience, cost, child preference, food safety and knowledge). Schools will be randomly allocated to one of two intervention groups. The program will run for approximately 10 weeks (one school term). The low dose intervention group will receive a 10 week program which includes weekly support messages delivered to parents using an existing school communication app and a magnetised parent resource booklet. The full dose intervention group will also receive a 10 week program consisting of the same weekly support messages and the magnetised parent resource booklet provided to the low dose group, plus the development of school based “lunchbox nutrition guidelines”, access to classroom curriculum resources and provision of a water bottle and ice brick to students. The weekly support messages (one message per week for 10 weeks) have been developed by public health nutritionists for the SWAP IT program and are consistent across the two intervention groups. These messages address the identified barriers to packing a healthy lunchbox and act as prompts and cues to reinforce the packing of everyday foods. Content includes short word messages, relevant pictures, links to videos and the project website and an email address to request further information. App analytics will be obtained to monitor message reach. The magnetised parent resource has been designed by public health nutritionists for the SWAP IT program and will be provided to parents in both intervention groups. This resource aims to facilitate the packing of a healthy lunchbox through the provision of tips and photos which can be accessed by parents at the time of packing. Schools allocated to the full dose will be provided with a lunchbox nutrition guidelines template, designed by public health nutritionists for the SWAP IT program and based on the SWAP IT program principles of packing a lunchbox full of everyday foods and swapping what is packed from sometimes to everyday foods. These schools will be supported by an experienced Public Health Nutritionist to modify these, ensuring applicability to their school community. Endorsement of the guidelines will be promoted to the school community utilising the authority of the school Principal, to communicate school expectations and normalise healthy lunchboxes. A copy of the school’s lunchbox nutrition guidelines will be forwarded to all families through the school’s usual communication channels.