Dr. Joel Furman's book, "Eat to Live" is excellent! I highly recommend that. He gives clear and informative explainations about foods, and his conclusions are quite liveable. He explains which foods are healthiest and should be the bulk of your diet, then he explains about other foods. You can still include other foods that you love in your diet, you just need to have the proper perspective and eat them in the proper (small to moderate) amounts.
You can also look at www.mercola.com. I have not read his book myself but it should be quite good, his recommendations are generally right on target.