The nutrient primarily responsible for muscle repair and growth is protein. Proteins are made up of amino acids, which are the building blocks that help to rebuild and strengthen muscle tissues after they undergo stress during exercise. Consuming sufficient protein is vital for athletes or individuals engaging in strength training, as it aids in recovery and enhances muscle hypertrophy. Ideally, protein intake should be distributed throughout the day to support constant muscle synthesis. Including various protein sources, such as poultry, fish, legumes, and dairy, ensures an adequate supply of essential amino acids.