Much has been written on nutrition over the decades. It's my opinion that, particularly in the last 20 years,there has been a lot of bad information masquerading as truth being promoted by people who are basically hustlers. Indulge me for a moments while I say a few things.
First off--I heard a speaker say one time that religion and nutrition were two areas where people could pass themselves off as experts yet possess absolutely no worthwhile credentials in their respective fields. Also, Adelle Davis wrote that people had a tendency to become fanatical about two things, nutrition and religion. I like her comment because I have seen people treat what they ate,and more importantly, what they didn't eat, with the same zeal a fundamentalist treats their faith.
Consider this analogy---Dave advertises that he runs a flight school and you want to learn how to fly one of those single engine planes. You come to my office and soon find out that I have not actually flown a plane myself but have read lots of books about it and have even operated a flight simulator. Would you then sign up for lessons from Dave the flight instructor? Of course you wouldn't,neither should you take advice from anyone simply because they claim to be a nutritional authority.
As a student of nutrition for around 40 years I may give you my opinion on what I think is a good way to eat but I believe it would be better if I told you what I have discovered in those 40 odd years in the health/nutrition field.
Hundreds upon hundreds of books have been written by people espousing their particular slant on nutrition, diet and what you should eat. The majority of these writers possess little credible schooling and knowledge on the fundamentals of nutrition and human anatomy. Claims that writers experienced near miraculous results from how they eat does not validate the worthiness of that claim. In addition, many of these writers who say they have this training or these credentials may have a diploma but they are from less than worthy institutions.
Here's the skinny--people need to take account of their own health and well-being. Don't depend on someone who makes a living promoting a special way of eating to give you unbiased advice. Call me cynical, but it's the truth. The internet is a great place to read and study about the basics of nutrition and the human body. Just like there are the fundamentals of athletic training, there are fundamentals of nutrition; such as the body's need for complete proteins, water, plenty of fresh vegetables as well as quality fruits and grains. Oh yeah, one other thing, when someone tells you that a certain way of eating is the best or only way to go, ask yourself this: Through the ages, are there a people on this earth who have lived long vigorous lives following the particular way of eating this person is promoting?
Don't be one of those people who compromise their health because they've been fooled by a smooth talking hustler. It's all about taking initiative, doing the work yourself.