Objectives. Recent efforts in health psychology to bridge the gap between individuals' intentions and behaviour have centered on the influence of planning strategies. This study investigated the impact of two commonly used types of self-regulatory planning in the prediction of health promoting behaviour. Design. This study employed a prospective longitudinal design. Three measurements were implemented in order to assess associations between various socio-cognitive determinants, planning, and health behaviour. Methods. Structural equation modelling (N = 572) was used to compare the value of preparatory planning, i.e. the planning of strategies and preparatory actions towards a goal behaviour, and implemental planning, i.e. the planning of when, where, and how to perform a goal behaviour, in the prediction of fruit consumption. Results. Both preparatory planning (beta = 0.21; p <001) and implemental planning (beta = 0.13; p <.01) were significant predictors of fruit consumption, over and above the influence of motivational factors. Comparison of differences in explained variance (Delta R(2)) indicated that the contribution of preparatory planning was larger than that of implemental planning (z = 2: 19; p <05). Implemental planning did not contribute to the prediction of fruit consumption over and above the influence of preparatory planning when tested simultaneously. Conclusions. The results provide a first indication that the planning of strategic preparatory actions may be more influential in predicting health behaviour than implemental planning, focusing on when, where, and how to enact goal-directed behaviour. Implications of the results and suggestions for future research are outlined.