Ask YC: What is/are the best book(s) you have read on nutrition?

It has been 3 months since I started dieting, and exercising on a regular basis as a plan to become a more healthy person. I have lost 20 pounds by now, and have gained some insight about how nutrition works by reading the hackers diet and articles over the Internet, however, I dont seem to get the full picture about how the whole process works, and would love to hear recommendations about some books that would help me understand about how metabolism, fats, carbohydrates, and everything else that is involved in nutrition operates.