Food Rules: An Eater's Manual by Michael Pollan
I found it to be simple and to the point, as well as short and completely worth the read. Essentially it is just a book of simple rules for eating wisely with an explanation for each rule. Check it out!
P.S. Support your local library by taking a book out from there. I have found the health and fitness section in my library to be an invaluable resource.
Disclaimer: None of the above photos are of me, and I do not take credit for them, they are merely on my blog to serve as fitness inspiration and are taken from various different internet sources.