About a year ago, I was introduced to the principles of Dr. Weston A. Price. Dr. Price was a dentist (not a nutritionist or medical doctor) who in the 1920's went on a global search for the perfect way to eat. Dr. Price found that in cultures where people still ate their traditional diets, they were healthy, had straight, cavity-free teeth among other things. Once these people adopted a western diet with processed foods, sugar and the like, their health was compromised.
Below is a link to Nutrition and Physical Degeneration, A Comparison of Primitive and Modern Diets and Their Effects written by Weston A. Price, MS., D.D.S., F.A.G.D. where you can read it for free.