Just ran across this. My mom-in-law was big on short term fasts, back in the ‘80’s. Guess she was ahead of the health curve.
I have only lost 3 pounds but I already feel so much better. And my head and thinking are so much clearer. I had noticed my thinking had become slightly foggy (the way I use to feel with a very tiny hangover). That's gone and it's only been about 3 days.
As an aside, I always eat keto, but I had been cheating around the edges (mostly with keto-friendly tortilla wraps for "sandwiches" and a few other putatively keto-friendly products).