Book goes into more detail about the science, and how your body produces and uses insulin. It's completely changed the way I approach food. My husband and I have followed this program for the past three months. We are both down 20+ lbs, which is saying something as we're both "north of 55". I am now recommending it for family, and purchased this most recent copy for my sister, who is down 18. No cravings. No hunger. If you can get through the first "hell" week as your body revolts to change and then adapts, you'll have tremendous energy and see food in a whole new light. Don't feel deprived and we go out to dinner a few times a week. Very livable program that you can stay on indefinitely, and actually enjoy it. It's not a diet. It's a true lifestyle change..FOLLOW UP REPORT 10/5/17: Husband and I are 30 lbs down each. I'm back to size 6-8, which haven't seen in years. Lots of energy. Generalized aches, pains and lifelong acid reflux? GONE!! Nexium? DONE with it. I don't miss the bread and other carbs. Have found peace with the program by replacing with treats that I love so. Quest bars are good, as are Ketobars and other treats when you want something sweet. Plenty of good offerings out there to keep you on track. Any for those with bad cholesterol numbers terrified by all the butter, cream, cheese and other great stuff? I had labs done before the program, then again 6 mos later. All my numbers improved by at least 25%. Who eats all this stuff every day and has triglicerides drop from a respectable 70 to an amazing 45?? (no, that's not a typo). BUY THE BOOK. Give it a try, but be consistent. Cheating by mixing carbs with really high fat foods is very bad.