Does Habit Strength Predict Junk Foods Consumption? An Extended Version of Theory of Planned Behavior

This study examined the utility of adding habit strength to the Theory of Planned Behavior (TPB) in predicting the intention and behaviour of junk food consumption. A Cross-sectional data were performed on 271 high school boy that sampled randomly from ten high schools in Bandar Abbas, Iran. Participants completed measures of the TPB, habit strength and food frequency in relation to junk food consumption. Hierarchical multiple regression analysis was performed to test the predictive power of the model. The traditional model explained 15% and 10% of the variance in intention and behaviour, respectively. Subjective norm and PBC (Perceived Behavioral Control) emerged as significant predictors of intention. Also, PBC and intention revealed as a significant predictor of behaviour. The extended model accounted for 28% and 11.6% of the variance in intention and behaviour, respectively. Habit significantly increased the explained variance in both intention and behaviour and emerged as the strongest predictor. Also, subjective norm and PBC remained as a significant predictor of intention and behaviour, respectively. The intention was a non-significant correlate of junk food consumption. Junk food consumption is more controlled by habit and PBC, rather than intention.