Planned exceptions

If I have written out a Planned Exception for sugar (as Brooke suggests to do this periodically, as a way to keep myself from feeling like it’s forbidden or addictive) and then on the day I had planned to eat it, I don’t actually feel like eating it, what should I do? The obvious answer seems that if I don’t even want the sugar, I shouldn’t eat it. But I wonder if NOT eating it will strengthen the mental pathway of making a decision based on my desire in the moment (primitive brain), rather than what I’d planned to do ahead of time (pre-frontal.)