In two experiments a self-regulatory strategy combining mental contrasting with the formation of implementation intentions (MCII) was tested for its effectiveness in diminishing unhealthy snacking habits. Study 1 (N = 51) showed that participants in the MCII condition consumed fewer unhealthy snacks than participants in a control condition who thought about and listed healthy options for snacks. In Study 2 (N = 59) MCII was more effective than mental contrasting or formulating implementation intentions alone and mental contrasting was found to increase perceived clarity about critical cues for unhealthy snacking. Together, these findings suggest that MCII is an effective strategy for fighting habits and that one of the underlying processes making MCII superior to implementation intentions alone may be that mental contrasting produces clarity about the critical cues for the unwanted habitual behavior. Copyright © 2010 John Wiley & Sons, Ltd.