"Back around 2015 I did six days a week every week for six months."

You only ate 1 day a week for 6 whole months??? Jesus effing Christ! That's inhuman discipline.

"The pangs go away, then come in waves, then the insomnia hits... "

Yeah, I dealt with the insomnia. It's kind of weird cuz you feel calm and serene like you could go to sleep easily, but you can't.

" ...and it causes some permanent physiological changes."

Can't say I've dealt with that. Didn't do it long enough I guess.

"Vigilance and clarity of mind are effects mixed in there but I deal with hypervigilance anyway."

Sounds like maybe a net positive overall?

"Would absolutely not recommend something that extreme to anyone else."

I wouldn't either.

"Also do not try to lift while fasting. lol."

Ha. Definitely not. I noticed that after about 3 days I had tons of energy. I would go on 10 mile walks and never get tired, but if I tried to hit the weights I crashed hard in about 30 minutes. I think it has to do with glycogen depletion in the muscles.