Sustainable Dietary Intentions Among Austrian Lower Secondary Students: Testing an Extended Theory of Planned Behaviour Framework

Sustainable food consumption is a key domain of sustainability education, yet lower secondary students’ dietary choices are shaped by evaluations, perceived feasibility, social expectations, family routines, and human–nature relationships. This study examined sustainable dietary intentions among 197 Austrian students aged 12 to 15 using an extended Theory of Planned Behaviour framework, including attitude, subjective norm, perceived behavioural control, nature relatedness, and environmental concern. Descriptive statistics, Pearson correlations, and path analysis were used. Students reported moderately high sustainable dietary intentions, favourable attitudes, and relatively high perceived behavioural control, whereas subjective norm was weaker and centred mainly on family expectations. Nature-relatedness showed coherent positive associations with intention, attitude, and perceived behavioural control. Environmental concern was positively associated with the TPB components but showed a more selective pattern. The extended path model explained 41.3% of the variance in intention to eat sustainably. Perceived behavioural control and attitude were the strongest correlates of intention. Nature relatedness was associated with the TPB components and retained a small direct association with intention, whereas environmental concern was not directly associated with intention. The findings suggest that perceived feasibility and nature relatedness are relevant correlates of sustainable dietary intentions in lower secondary education.