This is a follow-on companion book to Dr. Jason Fung's "The Obesity Code". Whereas "The Obesity Code" delves into the biochemistry of weight gain and loss and gets somewhat technical (the "why"), this book is written in a colloquial style and explains the "how" of intermittent fasting (IF) that is introduced toward the end of "The Obesity Code". I was expecting a cookbook, but was pleasantly surprised to find most of the book to be a discussion of what one will experience while fasting and how to do it in a way that avoids hunger pangs, light-headedness, and other effects one might expect when not eating in the way most of us do out of habit. Of roughly 300 pages, only the last 50, or so, are devoted to recipes and specifics of what and when to eat and drink. Co-writer Jimmy Moore, author of "The Ketogenic Cookbook", "Keto Clarity" and "Cholesterol Clarity", as well as podcasting "The Livin' La Vida Low-Carb Show with Jimmy Moore", provides his perspective on having actually done what Dr. Fung advocates. The book is sprinkled with short fasting success stories and each chapter has a list of references backing up what was written with solid scientific studies.