Let's get thing one thing straight right off the bat. Dieting doesn't work. Period. End of story.
What does work is permanently altering the way you eat, the way you train and exercise and the way you care for yourself (mind, body and spirit). In short, altering the way you live your life is what works.
A lot more will be added to this page but for now let's start with PDF's on the right hand side of the page. The first entitled "CrossFit Nutrition: Avoiding Metabolic Derangement" deals with the plague of the common American diet (and other places in the world too I'm sure), hyperinsulinsm and associated problems and diseases. A general prescription for a Paleo type diet is covered and Atkins and Zone history and methods are discussed. And more... This publication will tell you which direction you need to be heading in with your diet if your health, mental and physical well-being and athletic/physical performance are important to you. If they are not, you can quit reading now.
There is also a feed posted linking to Robb Wolf's site. There is more nutrition info. there than you can shake a stick at. Take a look, do some reading, educate yourself!
Also, check out the last link, Whole Nine, for a whole 'nother resource on nutrition and lifestyle.