Which macronutrient is the primary source of energy during high-intensity exercises?

Carbohydrates are the primary source of energy during high-intensity exercises due to their quick conversion into glucose, which can be rapidly utilized by the muscles for immediate energy needs. This efficiency is crucial during activities that require short bursts of intense effort, such as sprinting or heavy weightlifting, where the body's demand for energy is significantly increased.

In contrast, fats serve as a more sustainable energy source for lower-intensity, prolonged activities because they take longer to break down for energy production. Protein, while important for muscle repair and growth, is not a primary energy source unless carbohydrate stores are depleted, which is generally not the case during high-intensity activities. Fiber, on the other hand, plays a key role in digestive health but does not provide energy directly for exercise.

Understanding these roles helps nutrition coaches to design appropriate dietary strategies that optimize an athlete's performance based on the nature of their physical activities.