A randomised trial of an intervention to sustain the implementation of a healthy lunchbox initiative in primary schools

INTERVENTION: A randomised controlled trial will be used to test the effectiveness of a 6‐month theory‐based multi‐component strategy to sustain the implementation of a healthy lunchbo Xprogram within NSW primary schools located within 12 Local Health Districts of NSW. The healthy lunchbo Xprogram (‘SWAP IT’) consists of electronic messages sent to parents/carers via usual school‐parent communication channels (10 weekly messages in the initial school term, followed by 2 messages per term ongoing), together with school nutrition guideline implementation, curriculum/classroom resources, and parent resources. The SWAP IT 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 intervention of interest in this study is the intervention to sustain the implementation of SWAP IT. Sustained implementation of the program is defined as the distribution of 2 electronic healthy lunchbo Xmessages to parents/carers per term ongoing. The sustainability intervention will run for approximately 6 months (2 NSW school terms) following allocation to the intervention group. It will comprise seven sustainability strategies designed to support schools to continue implementation of SWAP IT as follows: 1. Develop and distribute educational materials Who: Local Health District health promotion staff will develop and distribute materials to school key contacts, who will share relevant resources with school staff and the wider school community. What: Educational materials will include: ‐an updated SWAP IT program guide containing an overview of the program and its components; the role and responsibilities of the school key contacts; actions required each term to sustain implementation; links to training and program resources; information about accessing support; the benefits of continuing SWAP IT; information addressing food insecurity and the cost of healthy eating; and a prompt to include SWAP IT implementation in the school workplan; ‐an updated healthy lunchbo Xguideline/policy template outlining the importance of healthy lunchboxes, examples of healthy lunchboxes, how the school supports healthy lunchboxes, and formal school endorsement of continued SWAP IT implementation; ‐new parent factsheets providing practical information on budget‐friendly healthy lunchboxes, food affordability and food security, and nude food/waste‐free lunchbo Xideas; and ‐links to existing SWAP IT implementation resources, including staff training, lesson plans and other program resources. When/frequency: The program guide will be distributed by email in weeks 1, 4 and 7 of each school term. The healthy lunchbo Xguideline/policy will be reviewed and endorsed annually. Parent factsheets will be available throughout the intervention period. Where/mode: Materials will be delivered electronically via email and made available through the SWAP IT website (portal). Schools will implement the materials within thei CONDITION: Diet and Nutrition ‐ Obesity Obesity; ; Obesity Public Health ‐ Health promotion/education PRIMARY OUTCOME: Proportion of primary schools distributing the recommended number of SWAP IT messages (2 messages per school term) to parents/carers at 6 month follow‐up[A study specific survey administered online or via telephone to school principals (or their delegate or SWAP IT key contact) will assess the sustainment of the SWAP IT program at 6 month follow‐up. The survey will assess the number of SWAP IT messages sent to parents/carers during the previous 6 months (ie 2 school terms). The SWAP IT program will be considered successfully sustained if primary schools report distributing 2 messages to parents per school term (total 4 messages distributed throughout the study period). 6 month follow‐up] SECONDARY OUTCOME: Mean number of SWAP IT messages sent to parents/carers at 6 month follow‐up[A study specific survey administered online or via telephone to school principals (or their delegate or SWAP IT key contact) will assess the sustainment of the SWAP IT program at 6 month follow‐up. The survey will assess the number of SWAP IT messages sent to parents/carers during the previous 6 months. 6 month follow‐up] INCLUSION CRITERIA: Department of Education (DoE), Catholic and Independent primary schools located within 12 Local Health Districts of NSW (Murrumbidgee, Hunter New England, Sydney, Western Sydney, South Eastern Sydney, Northern Sydney, Western NSW, Nepean Blue Mountains, Illawarra Shoalhaven, Central Coast, Mid‐North Coast, Northern NSW). Primary and combined schools who cater for primary school aged children that have implemented the SWAP IT healthy lunchbo Xprogram since the beginning of 2023 will form the study sample and will be invited to participate.