Couldn't hurt.... everyone is so different when it comes to their bodies that while one diet may work for x number of people a different diet will work for those that couldn't experience change with the first one.... so my theory is learn all i can about nutrition.... i have found out my body works the best when i eat moderate to low carbs but making sure that most of the carbs are lower GI... now my training partner who is an extomorph cannot use my same diet and experience the same results.
I have one of his books and it was not worth the dough.
It was a good read if I was inexperienced and had no knowledge of nutrition. But since I have that it was not worth it. Learned a lot more from boards and articles on the net.