I like your idea of following a Plan written out ahead of time. I've been doing that for years...not just with Fasting, but Eating as well. It'll tell you what you're made of.
I have found, in my past cases, that I can conquer the World on a full stomach. But when hunger hits....well, that's a different story.
I feel the 'key' is having Purpose in Life. Without it we tend to wallow in our own mud......WY