While watching Matt's most recent video he discusses the mental aspects of dieting, in particular good food and bad food. Within it, they stress the importance of ridding yourself of food anxiety (they give the example of feeling bad when having a pizza), and acknowledging that while having something that would be considered bad is not the end of the world at all, provided you don't let it spiral out of control.
It is definitely an enlightening discussion. Although the idea of food anxiety was unfamiliar with me beforehand, it is certainly something that I have experienced myself. It did make me wonder though how important diet is overall when trying to stay fit. Would you say that is more important than exercise?