This book provided me with a new way of thinking about food and how it affects health and energy levels. Her explanations can be pretty "alternative" and many of them are not grounded in medical science, but as long as you're aware of that, this is a very practical book. As she points out, there are many connections in this world that conventional science is only starting to discover. Colbin's ideas work when put into practice.
If you're open to new ideas about food and diet, read this book. If you want to be vegetarian but don't feel good on a vegetarian diet, or if you aren't happy with how you eat but aren't sure what to do about it, read this book. She makes few judgements and refuses to label foods (or diets) "bad" or "good" - she just tells you what effects she's obseved and lets you draw your own conclusions. I appreciated her awareness that everybody's different; that depending on your climate, the season, your personal biochemistry, what you have eaten previously in your life, and even your job, your dietary needs will differ.
Colbin's cookbooks ("The Natural Gourmet" has delicious recipes) put her ideas into practice and prove that you can eat the way she recommends without feeling deprived.