Make a reason compelling

Hi there,

I am wondering how can I make my reason compelling enough when it is not. I am fasting and my reasons for fasting like 1) having a better body composition and 2) becoming able to manage my mind in front of the storm of thoughts creating doubt, discomfort, depleted when I fast seem to not be compelling enough. So that my brain finds room to say “Why are you doing it?”. This make me end up in a rabbit hole of resistance to me doing it. Now, the alternatives would be to just stop doing it, simply witnessing that my reasons are not compelling enough, or try to use it as an exercise to see if I can create compelling reasons on purpose. But I am not sure how to approach this. Suggestions? Thanks a lot