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

A randomised factorial design will be utilised to test the efficacy of an app only and app plus school guidelines 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 either one of two intervention arms or a waitlist control group. The program will run for approximately 15 weeks. The app only (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 app plus school guidelines (medium dose) intervention group will receive a 15 week program consisting of the weekly support messages and the magnetised parent resource booklet, plus the development of school based “lunchbox nutrition guidelines. An experienced public health nutritionist will work with schools to develop lunchbox nutrition guidelines. Schools will be provided with a guideline template, based on the SWAP IT program principles, and will be supported to modify to ensure applicability to their school community. Principal endorsement of guidelines will be promoted to the school community utilising the authority of the school principal, to communicate school expectations and normalise healthy lunchboxes. Following the development of the guidelines, weekly support messages will be delivered to parents using an existing school communication application. Parents will also receive a magnetised parent resource booklet. The weekly support messages 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 may include short word messages, relevant pictures, links to videos and project website and an email address to request further information. The magnetised parent resources has been designed by public health nutritionists for the SWAP IT program and will provided to parents in both intervention groups. This resource aims to facilitate the packing of healthy lunchbox through the provision of tips and photos which can be accessed by parents at time of packing.