Even the European Union supports protein-rich diets

When you're talking about trying to build lean muscle tissue or “bulk up,” you've probably heard that protein-rich diets can help you gain muscle. It's true that protein does contribute to muscle-building, but too much protein in your diet actually — more than you probably already eat — potentially can harm your efforts to grow lean muscle tissue.
Muscle-Building Facts

Protein in your diet helps to build and repair muscles, but when it comes to adding lean muscle mass, carbohydrates actually represent a much more important energy source than protein, according to the University of California at Los Angeles. That's because your body needs mainly energy and calories — not protein — to create new muscle tissue, and carbs provide a much more readily available source of energy than protein. In addition, your body stores carbs, not protein, in your muscles as energy that it can draw upon during strenuous workouts.