Bob Greene's book should not be labeled a diet book, so much as a book about changing one's lifestyle. Using his four-step process, I was able to rejuvenate my exercise and diet regimen and managed to lose about 20 pounds. Much of this was fat, as the fourth phase of Greene's plan emphasizes muscle building.
This book is probably best suited for beginners. Greene's message addresses losing weight, improving cardiovascular health, understanding why you eat (emotional eating, ala Dr. Phil), and improving self-esteem. Greene also advises people not to eat after 7pm, which I believe may be based on the false premise that a person's metabolism shuts off during sleep. According to Greene's plan, you should change your lifestyle in fours phases: 1) find out where you are at, what got you there, and what you want to achieve; 2) implement an aerobic exercise routine; 3) get to know what emotions are working to cause you to eat in excess of your body's needs; and, 4) build muscle with anerobic exercise.
If you already exercise regularly and are knowledgeable of sound nutrition concepts, you may not need this book. However, if you're like me, you may find Greene's book motivational and thus worth the money and time.