Feasibility of an online nutrition intervention to improve adherence to healthy and sustainable diets in young Australian adults: protocol for a pilot pre-post intervention study.

Introduction: Current diets which are commonly high in meat and ultra-processed foods are unhealthy and unsustainable and contribute significantly to climate change, environmental degradation and poor health outcomes. Transitioning to healthy and sustainable diets that are rich in plant-based foods and low in animal products could reduce environmental impacts and improve population health. Young Australian adults are a critical target group for dietary intervention as they are motivated towards climate action and have the lowest diet quality out of all adult age groups. As such, this study proposes a digital nutrition intervention to promote healthy and sustainable diets in this population group.

Methods And Analysis: A 4-week pilot pre-post intervention will be conducted on the Deakin Wellbeing mobile application between July and August 2025. 32 young adults (18-25 years old; current student and/or staff at Deakin University; consume less than 260 g/week of legumes or 175 g/week nuts, living in Australia) will receive 4 weeks of the intervention to improve their adherence to a healthy and sustainable diet. Primary outcomes include feasibility (retention rate) and acceptability (engagement and user experience). Secondary outcomes include sustainable food literacy, legume and nut intakes, and adherence to a healthy and sustainable diet. Primary outcomes will be reported with descriptive statistics, while changes in secondary outcomes at each study time point will be measured using repeated measures Analysis of Variance, Friedman tests and McNemar's tests.

Ethics And Dissemination: Ethics approval to conduct the study was granted by the Deakin University Human Research Ethics Committee (2024/HE000163). A summary of findings will be disseminated to key stakeholders, for example, Deakin University Student Engagement groups, and will also be presented to the wider research community at conferences and via peer-reviewed publications. A summary of the results will be sent to all participants via email.

Trial Registration Number: Australian New Zealand Clinical Trials Registry Registration ID: ACTRN12625000335493p, prospectively registered on 22 April 2025. Universal Trial Number: U1111-1319-0745.