Fat Chance by Robert Lustig
In all honesty, I skimmed parts of this book because the author gave more detailed information than I really was interested in. That said, it was a really good book.
Salient points made include:
1. Weight gain/loss is much more complicated than the usual gluttony/sloth blame game.
2. Eat less sugar, especially HFCS, and more fiber.
3. Eat real food.
Nothing that we didn't already suspect.