In Defense of Food, by Michael Pollan
Eat Food, Mostly Plants, Not Too Much. A 7 word summary of the book that sure makes it sound simple. And in a way, it IS that simple. Once you realize what is REAL food versus 'foodlike edible substances', and lot's of other basic guidelines. Oh, but how we have been hoodwinked by Mega Food companies, our own FDA, and misled by well-meaning but unreliable 'nutritionists'. I give it 4.5 stars. Very important, very educational.
Here's a good video of the the author, discussing the book: