Can improvements in the nutrition quality of lunchboxes, following an app-based intervention, be maintained with or without support.

A randomised factorial design will be utilised to test the efficacy of booster messages in maintaining improvements in the nutrition quality of primary school lunchboxes. All schools have received the app-based intervention which aimed to improve the contents of primary school aged 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 sought to address the barriers faced by parents to packing a healthy lunchbox (time/convenience, cost, child preference, food safety and knowledge). The fifteen week program delivered to schools during 2019, consisted of: 1. Development and dissemination of lunchbox nutrition guidelines 2. Weekly support messages (via the school communication app) 3. Resources for parents (booklet, water bottle and ice brick) 4. Resources for schools (classroom flipcharts and lesson plans) Following the post baseline data collection for the trial listed above, schools will be randomly allocated to an intervention group or control group. The intervention group will receive two booster messages, delivered via the school communication app, SkoolBag. The first message willl be delivered approximately six weeks post the app-based intervention and the second will be delivered one month later. The booster messages have been developed by public health nutritionists for the SWAP IT program. These messages address the identified barriers to packing a healthy lunchbox and act as prompts and cues to maintain the packing of everyday foods. Content, based on barriers identified by parents and engagement with original weekly support messages, may include short word messages, relevant pictures, links to videos and the project website, and an email address to request further information. Intervention schools may also receive professional development, policies and/or resources similarly to schols allocated to the "Usual Practice" control condition.