The nutrient primarily involved in energy metabolism is carbohydrates. They are the body's primary source of energy, particularly during high-intensity exercise. Carbohydrates are broken down into glucose, which is utilized by muscles and organs for immediate energy or stored as glycogen for later use. While proteins and fats also contribute to energy production, carbohydrates are especially vital for athletes and individuals engaged in endurance sports. A diet rich in complex carbohydrates supports optimal performance and recovery.