You've fasted for a month once or twice, do I read that right? Did you do any kind of write-up about it, a blog, anything? Very interested in your experiences.
No, I did not do any write-up. /r/fasting and /r/keto will probably satisfy your curiosity, but I will mention the following which are not entirely common (or not commonly described):
. my B12 normalized from "very low, needs supplements monthly" which it had been in for 6-7 years at that point, to "slightly above normal without any supplement", and is still there some 20 years later.
. libido went away for the fast, but came back later
. felt perfect, exercised, etc, but friend observed that I was moving much more economically - e.g. that I was lifting my feet only about 2mm above ground while walking. I didn't notice that until he did.