Loving my reason vs. Making excuses

I can see how deciding to love my reasons for something can very easily become a way that I excuse myself for not doing hard things, or not following through with certain things.

For example, if I decide that today I’ll challenge myself by not eating sugar, and then in the moment have a craving to have sugar, I can easily tell myself, “Well, it’s just a bite and this is a very valid reason to have sugar” and then love that reason.

How can the concept of loving my reasons not be used as an excuse? Or not lead me into always giving myself an excuse?