I own and have read this book as well as the newer follow up (published in 2004).
This book is now nearing 15 years old. I read it very recently and began to employ the methods taught in the book. It was not until reading Kurzweil's newest book that I saw he has changed many of his ideas since the writing of this book in 1992-93.
For example; in 10%, you should not eat more than 10% of your calories from fat. Carbohydrates are encouraged, sugar is not *that* big of a deal, and caffeine is the enemy. In the new book, fat can be 25% of your calories each day, carbohydrates must now stay very low, sugar is to be avoided at all costs, but caffeine is ok! In fact, the author now drinks 8 cups of green tea per day. Green tea is lower than coffee in caffeine, but 8 cups a day is still a lot of it.
I enjoyed reading this book, but I wish I had realized that the information contained within was out of date and no longer to be followed. It would have saved me $20.