Why do bodybuilders eat carbs before a competition..seems like they should be doing protein?

High carb diet : Actually a high comlex carbohydrate diet is recommended before any sterenous exercise, such as running a marathon. Complex carbohydrates like pastas are different from simple carbohydrate like sugar because they are metabolized slowly to provide sustained energy that is needed for ptolonged, sterenous exercise. Proteins are not a good source of energy.