Journalist book on fasting

I loved the documentary Arte because it showed the "scientific" aspect of fasting and well described autolysis, the period that occurs 2 or 3 days after the start of fasting when the body begins to consume its fat and proteins.
I have not found this in the book. It is rather an investigative book on the history of fasting. Interesting, but not very practical for someone who wants to fast. Instead, I recommend the book of Helmut Lützner for practice.