Why We Get Fat and What to Do About it by Gary Taubes
In the Introduction, Taubes is upfront. He basically writes that if you want to lose weight, don't eat carbs. If you don't want to read the book, that pretty much sums up the rest of the book.
I tried reading this book awhile ago but it didn't take, but it wasn't until I was seriously trying to figure out how to change my diet that I was drawn into this book. Surprisingly accessible, practical, and readable.