The most important macronutrient for endurance athletes is carbohydrate. Carbs serve as a primary energy source during prolonged physical activity, helping to maintain glycogen stores in muscles and the liver. Adequate carbohydrate intake supports sustained performance, improves recovery, and enhances training adaptations. While proteins and fats are also important, they play a secondary role compared to carbs in supporting endurance. Endurance athletes should focus on a diet rich in carbohydrates, especially around training sessions, to optimize their performance.