Protein plays a crucial role in muscle building by providing the essential amino acids required for muscle repair and growth. Following resistance training, protein consumption stimulates muscle protein synthesis and helps facilitate recovery. It also contributes to creating a positive nitrogen balance, which is essential for muscle maintenance and development. Recommendations for protein intake vary based on activity level but generally suggest higher consumption for athletes and individuals engaging in intense workouts. Including a variety of protein sources, such as lean meats, fish, legumes, and dairy, can optimize muscle-building efforts.