The truth is that keto does not work for everyone. Just a fact that we're all different. Also, keto means different things to different people. To some in includes fasting. This can be very dangerous, even fatal, if you are a real diabetic (Type I: pancreas not working as designed).

I did he "carb loading" years ago when it was hip, along with high protein. My endurance improved. Then carbs became evil so I did that. Not so good. Back to moderate carbs but only ones that taste good :-).

My wife is very low carb, started keto, with some adaptations, and is doing well. I tried it and endurance went to crap and I found I had to eat much more often to keep up my energy. This is not good when you travel a lot. She tried the fasting and it was very bad. She found things like carrots and most fruit to be bad for her blood sugar (more carrots for me :-).

Humans are irritatingly varied creatures :-).