Young adults' intention to eat healthy food: Extending the theory of planned behaviour

The present study predicts adults' intention to eat healthily, using the th eory of planned behaviour (TPB) and additive and moderating effects of role identity, group norms and group identification, derived from identity theo ry and self categorisation theory. A total of 735, 25 years old adults part icipated in a mailed questionnaire survey in 1997. The TPB explained 52% of the variance in young adults' decision to eat healthily, with perceived be havioural control and subjective norms being the strongest (beta = .56, p < .001) and weakest (beta =.05, p < .005) determinants, respectively. Althou gh, role identity accounted for an additional amount of 4% of the variance in behavioural intention, past behaviour did not moderate the impact of rol e identity on intention, as hypothesised. Neither perceived group norm nor group identification added to the prediction of intention over and above th e TPB. However, group identification was found to act as a moderator on the relation between group norm and behavioural intention in the predicted dir ection. The wider social context seems to play a stronger role for the form ation of adults' healthy eating decisions than indicated by the TPB.