If you're looking to cut your portion sizes down, I would recommend The Portion Teller by Dr. Lisa Young. For her Ph.D. thesis she did an extensive analysis of the portions of food sold in restaurants, street food vendors, fast food places and in prepared foods in grocery stores in the US. What I learned from the book:
1. The sizes of foods sold and consumed have increased dramatically in the US post World War II (she has some really interesting sidebars that are timelines showing how, for example, a Hershey chocolate bar has increased in size over the years).
Also, looking at old sets of dishes from the 1940's you can see how food sizes have changed. Dinner plates today are gigantic. My coffee mug could hold 2 servings of coffee, and I drink 2 full mugs per day! I already knew some of this before reading the book, but it is eye-opening to see it quantified.
2. Calorie counts on packaged foods are not accurate. She recounts a story of several dieticians given the task to determine the calorie count and nutritional content in a meal, and they all had different answers.