As you point out there are cycles that will influence the experience of a fast - not limited to physical energy available at any time, possible discomfort due t

As you point out there are cycles that will influence the experience of a fast - not limited to physical energy available at any time, possible discomfort due to coping mechanisms food/eating may part of, and so on. I am still managing significant chronic pain, and although sugar is bad for inflammation - which has its own problems - it is "comforting" and numbs the pain to some degree as well. I generally go through cycles of pure water fasting for 3 days to break the sugar cravings and to bring back mental clarity, at the cost of the remaining pain localizing and becoming sharper. Still waiting for refuge from pain, potentially some more healing next week, and then have to wait another ~3 months for another stem cell treatment.