Welcome to the wild West wellness and longevity conference. Say any old thing and hope it sticks, if it doesn't , reverse ferret and say something else.
It's not new that extreme fasting is potentially harmful. Did he not also take a diabetic drug for diabetes that he doesn't have for some other belief that it was good for metabolism, or something? Biohacking self-experimentation reasons, fair enough each to their own but he's a doctor and taking drugs is not good for you, kids. Take it from me, I'm nearly 60.