And then, there's the Perfect Fit Questionnaire - forty three pages of multiple choice questions about personal preferences, eating habits, exercising habits, laboratory values, and family history that, like one of those internet personality quizzes, places the reader in one of three categories - carbohydrate counter (low carb), calorie counter, or fat counter. Answers to the quiz also direct the reader to sections of the book that cover advice on how to adapt the various diets to reader taste and temperament.

And, finally, if you're unlucky enough to fall into the "carb counter" category, you have to test your urine for ketones for the first two to three months of the diet, to make sure you're not eating too many carbohydrates. (Restricting carbohydrates makes the body use up its fat stores to provide energy. Ketones are a by-product of that process.) It's an extra step that helps the carb-counter monitor their progress and adherence to the diet, but it's also one that's likely to turn a off a lot of dieters.

It is a very sensible approach, and one that is likely to work, if you're willing to put in the work. Unfortunately, when it comes to weight loss, what the public wants is a magic bullet. That's why weight-loss pills and surgery are so popular. And unfortunately, that's why Dr. Sanders, as sensible and honest and medically sound as her book is, isn't likely to garner the glory and fame of an Atkins or an Ornish. As Dr. Sanders puts it:

Albert Einstein once defined insanity as asking the same question over and over and each time expecting a different answer. If that is true, we are a nation of nuts. We go on weight-loss diets to get rid of the weight our "real diets" have put on us. Then, whether we are successful in our weight-loss diet or not, we go back to our old diet and, whad'ya know, if it made us gain weight before, it will do so again, because nothing has happened to change that diet.....You have to change the way you eat every day. And that is not easy.

There's nothing easy about the Perfect Fit Diet, either. But if you have the fortitude to examine yourself and your habits honestly and to stick with it - forever - it's much more likely to take off the pounds and keep them off than any of the other diets on the bookstore shelves.