Beware of trying to suppress a thought or a command to yourself like "you shouldn’t eat" that, because it could backfire on you and actually make the thought more pronounced.
Let’s say you were clipping along on your weight-loss program. Your diet motivation had been excellent, and you didn’t have one diet cheat yet. You were four weeks into your diet plan. Four weeks, did you hear that? You were ecstatic. But—and there always is a “but”, isn’t there—thoughts of having some lemon meringue pie have been sneaking into your mind. So you tell yourself, “I shouldn’t eat any lemon meringue pie”.
Here’s what the research shows. It will be harder for you to resist eating some preferred piece of pie if eating pie has been a strong habit of yours in the past. Nevertheless, if you tell yourself “no pie, no matter what pie has meant to you in the past, whether it’s been a strong habit of yours or not, you are likely to violate your good diet plan and go for a piece of lemon meringue pie.
The solution: Don’t tell yourself no. Instead, when pie cravings rear their pretty little heads, have a plan to counteract them that takes the positive high road. For example, “When I feel like having some pie, I will _____________ instead.” Do a substitution if you can. “I will double up on some good diet food.” Or, you could plan to double your reward for sticking to a diet. There are lots of ways to go about saving your good weight-loss progress. Trying to control the urge by telling yourself no or not to, is not one of them.

