I was boxing up some of Sarah's books and ran across Enzymes The Key to Health by Howard Loomis. It was last updated in 2007, so I imagine even more has been learned since then.
Basically, we need enzymes to digest our food! Enzymes come from raw fruits and vegetables, so all our cooked, processed foods do major damage to our bodies. Our bodies can produce some enzymes, but not enough to take care of all that we eat.
The book discusses the history of nutrition as well as the many errors and deliberate choices made that have caused damage to our bodies. For example, scientists have worked to slow down and eliminate the enzymes in fruits and vegetables so they have a better shelf life. Even though our bodies need the enzymes, the concern is more for the grocer being able to keep the product on the shelf longer.
Also, I learned that the body is complicated! Just the way of using enzymes in digestion of different foods is amazing. Carbohydrates, fats, and proteins are all digested in unique ways. I came away thinking that there is no way for a serious scientist to think these processes developed through evolution. They can not be accidental.