It is actually true that within the first hour after working out intensely with weights, the body is in a special metabolic state whereby protein and carbohydrates will be more rigorously partitioned toward muscles, and away from fat cells. This is because during this period, insulin sensitivity is extremely high, which means amino acids and carbs will very readily be absorbed, assimilated and stored directly into damaged muscle cells. This allows for repair, recovery and recuperation to start immediately, and over time will result in far better results than eating your post workout meal outside of this anabolic window.