A few days ago, I posted a video about the problem with sugar, particularly fructose, and management of weight. Today, I watched another video of a lecture given at UC Berkeley by award-winning science journalist Gary Taubes. This provides an alternative hypothesis to the calories in/calories out standard. It's VERY compelling watching. Also available in his book Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health.
You can watch the video here. It's an hour and a half, but has completely convicted me of important changes that need to be made in my diet and the diets of my family.