I just wanted to share a quick exerpt from a book I'm currently reading "Omnivore's Dilemma" by Michael Pollan.
"The recent discovery of these secondary metabolites in plants has brought our understanding of the biological and chemical complexity of foods to a deeper level of refinement; history suggests we haven't gotten anywhere near the bottom of this question, either. The first level was reached early in the nineteenth century with the identification of the macronutrients-protein, carbohydrate, and fat. Having isolated these compounds, chemists thought they'd unlocked the key to human nutrition. Yet some people (such as sailors) living on diets rich in macronutrients nevertheless got sick. The mystery was solved when scientists discovered the major vitamins-a second key to human nutrion. Now it's the polyphenols in plants that we're learning play a critical role in keeping us healthy. (And wich might explain why diets heavy in processed food fortified with vitamins still aren't as nutritous as fresh foods.) "