I've been on a weight rollercoaster for the past 10 years, varying between 180 and 230 lbs and I've read many of the same books the author names, and while they all may lead to self-discovery on what makes YOUR body tick, none of them contain the mystical ONE THING that will cause you to lose 20 lbs in one week. In this I agree whole-heartedly with the author.
For those that are very overweight, I do highly recommend the advice to change your diet first, without starting an extensive exercise regimen. Many folks' regular diet is so bad that just eating healthy food and drinking water will cause them to lose 5+ lbs in the first week. You need to buy-in early on to the idea that exercise isn't about burning off the food you ate (as that's impossible) but about raising your metabolism and conditioning your body.