I have read “It Starts with Food” numerous times. It’s the book that kicks off starting the Whole30, written by Dallas and Melissa Hartwig , the man and woman behind the Whole30 diet.
It details the reasons they created the diet, the symptoms you should expect to experience while “detoxing” from sugar and the other foods, why you need to be strict and start over if you slip and how to make the changes.
It’s a fairly long read, but worth reading and rereading each time you’re getting ready to start. It’s a very informative guide to Whole30 and was written to go along with your prep to start Whole30.