There's a book out called Neanderthin. It was a pretty good read, Author made many good arguments against eating grains, dairy, sugar using paleo studies and archelogical stuff.
There is certainly a case to be made against eating processed food, one article I read on a paleolithic diet claimed that processed food could be the cause of as many as 75% of fatal diseases today.
Cardiovascular disease, cancer etc are said to be mainly a cause of new foods.