No, not particularly helpful...that seems more like brainwashing, and if you are going to be that rigid, your chances of going off track are actually much higher. Personally, I think it is more important to figure out how to correct and compensate for slip ups than to think you can always control them from happening to begin with...you can't control for every possibility and it's better to learn how to deal with it, IMO.
Yes, it IS hard. There are a lot of things in my pantry that are calling my name this instant! That's why I'm typing and chewing gum