I've been reading lots of books about food in the United States and I thought I'd give you a whiz-bang snippet of what I've read.
What To Eat, Marion Nestle
Granted, I read this book about 2 years ago, so my memory is a little fuzzy. What I do recall: its an enormous book (the hardcover is 9.3 x 6.4 x 2) and she methodically tells you what to eat and why. (I took lots of notes.) Highly recommended, but I suggest you pace yourself.
Don't Eat This Book: Fast Food and the Supersizing of America, Morgan Spurlock
I figured there was nothing left to talk about after the movie, Supersize Me, came out, but I was wrong. Although I heavily skimmed this book, he did have some neat things to say. Including giving props to an elementary school in Olympia, WA that grows their own food. When I told my teenage niece about the mention (she lives in Olympia), she scoffed. "Oh yeah. That school. Mine didn't do that." The main points of Spurlock's book were that schools in the United States serve crap to our kids, and that fast food joints sell more chemicals than food.
The Omnivore's Dilemma: A Natural History of Four Meals, Michael Pollan
Another big book, but definitely worth reading. I learned a lot about farming correctly, and how the United States "demands" farmers grow too much corn, and then invents things to use up the supply (e.g. high fructose corn syrup, feed it to cows, make ethanol). Some of his stories got a little long winded, but that is what skimming is for.
Harvest for Hope: A Guide to Mindful Eating by Jane Goodall
Jane Goodall is one of my Mom's heroes. I once had to take a picture of my Mom standing behind Jane Goodall, because my Mom did not want to bother Jane by asking if she would pose for a picture. (We were at a book signing.)
I abandoned the book after 5 pages. After reading Pollan it felt like I was reading a book written for first graders. Back in to the library bag it went.
Animal, Vegetable, Miracle: A Year of Food Life, Barbara Kingsolver
Far and away the most beautifully written, almost lyrical of the bunch. Never lecturing, but certainly skewering things, such as being vegetarian because you don't want "animals to suffer". Normally, I hate, hate, hate, it when recipes are added to novels, but the authors did a great job of adding them more as side notes, then as text. (And I found myself scrambling for pen and paper to remind myself to jot them down later.) I did skim (I always do) but it is truly a beautiful book. Highly recommended.
I suggest you read, in this order: Animal, Vegetable, Miracle, What To Eat, and then The Omnivore's Dilemma (assuming you've made it through the first two).
Or, you can just sit at your local farmer's market and let your eyes and nose tell you what you should be eating.