I followed Dr Klaper’s online protocol for doing a fast and elimination diet. I made it 65 hours on a water fast at home, but was so weak I didn’t want to go further without medical help (you should never fast more than 3 days unless you are at somewhere like True North where they can monitor yo. Well that’s all it took for me anyway.
https://www.amazon.com/Pleasure-Trap-Mastering-Undermines-Happiness/dp/1570671974