Adherence to and factors associated with the adoption of healthy and sustainable diets in young Australian adults: a cross-sectional study.

INTRODUCTION: Transitioning toward healthy and sustainable diets is needed to address health and environmental challenges. Young Australian adults have poor diet quality and are thus a pivotal age group for healthy and sustainable dietary intervention. As such, the aim of the study was to examine the adherence and factors influencing adoption of healthy and sustainable diets in young Australian adults. METHODS: Young adults (aged 18-25 years) living in Australia completed an online survey (n = 297) which assessed their knowledge, attitudes, barriers and enablers toward healthy and sustainable diets. 107 of the 297 participants completed up to four Automated Self-Administered 24-h diet recalls. Diet recall data were used to calculate adherence to healthy and sustainable diets using a modified version of the World Index for Sustainability and Health (mod-WISH) score. Associations between demographic factors and knowledge, attitudes, barriers, enablers, and mod-WISH score were assessed using univariable and multivariable linear and logistic regression. RESULTS: Mean mod-WISH score was 49.3 ± 14.5, out of a total possible score of 130. From the multivariable models, those following a plant-based diet had higher mod-WISH score compared to those following a non-plant-based diet (p = 0.024). Most participants were not aware of healthy and sustainable diet guidelines, and did not perceive these diets as convenient, affordable or accessible. Preferences and perceived health benefits of meat and dairy were identified as key barriers to following these diets. Compared to females, males were less likely to report that understanding animal welfare concerns motivated them to adopt these diets (p = 0.008) and were more likely to report that their preference for meat was a barrier to following these diets (p = 0.016). Moreover, full-time employed young adults were less likely to perceive healthy and sustainable diets as convenient (p = 0.019), while those who were part-time/casual employed were more likely to agree that having greater access to healthy and sustainable food environments encouraged them toward these diets (p = 0.029), compared to unemployed young adults. CONCLUSION: Findings from this study emphasize the need to target young Australian adults in healthy and sustainable dietary interventions. Furthermore, results may be useful in the planning and development of such interventions.