Originally written in 2008 when “fasting” was still an evil word in the diet industry.
It goes more into science and story about IF (If you know all that probably can skip half of it).
Some of the later chapters have additional info from over the years.
More studies have come out but the message is still the same.
In the end it’s a “TOOL” to use in your lifestyle…and not everyone will use it (or should use it) the same way.