Happy to continue the conversation
I just finished writing you a detailed answer and it somehow didn't get posted! So here I go again.
I appreciate the opportunity to answer some of these questions. I'll do the best I can.
The format of the book, in terms of the Rules and focus on Primarian plan, was what I needed to do in order to get it published. When I first tried to sell the idea of a maintenance book to agents, they said it would never sell to a publisher. The reason was that publishers (according to knowledgeable agents) would not take a book that did not address a perceived problem. In their view, people who had completed a diet did not feel they had a problem any more!
This argument ran completely counter to my own professional experience. I interview new patients every week, and almost without exception they have lost and regained weight many times. They are completely frustrated by their inability to maintain. I was finally able to convince a book agent on this point. I then presented the book at a writer's conference for physicians in Boston. I was advised by publishers there that the book needed "rules". I guess there are certain formats that seem comfortable to buyers from their point of view. Since my main goal was to get the topic of maintenance into public view, I worked to create a book that would be saleable.
As it turns out, the rules I went with actually do form the backbone of the maintenance plan I advocate. However, there are many other rules and behaviors that are kind of buried in the text.
In terms of making a drastic change from the weight loss diet to maintenance, that's actually not the case for the patients I treat. We reduce them with a combination of liquid supplement during the day and a Primarian meal at night, plus snacks. They are already comfortable with this style of eating and we simply add back more Primarian-type food when they enter maintenance. In truth, a Primarian diet is not as drastic as you may think. I have suggested that people choose basic (non S foods) 90% of the time That means, most-- but not all by any means. I picked 90% because I find that a tough message means that maintainers give more thought to their departures. I completely understand that people will add back bread, pasta and even sweets. But I really want them to think about it and to realize that the potential for re-triggering of their old eating patterns lie mostly in those foods. I also firmly believe that the tendency to overproduce insulin and therefore store fat more avidly, remains in POWs (previous overweight people). If you give yourself too much of a chance to slip back into the insulin cycle, you'll start gaining.
You astutely have observed that this book is really not targeted at those who are already successful in maintenance. You, and many of your readers, have already figured it out and so merit the title of experts! Success is the real marker of good maintenance and any program that works for an individual is acceptable, as long as it's healthy. The next book should look at all the different takes on maintenance that individuals have developed. Maybe you'll write that one!
Lastly, your question about 'what if this doesn't work?' The answer is: this is just one approach. If this were a weight loss diet, someone could put this book down and go read Ornish, Atkins, Agaston, Dr. Phil, Suzanne Somers...etc, etc... Unfortunately, maintenance plans are currently few. But I hope that this will be just one of many books to come on the topic. In the meantime, we all have to continue to do our own personal science, as i mentioned above. Let's all work together!