Which macronutrient is primarily utilized for high-intensity exercise?

Carbohydrates are primarily utilized for high-intensity exercise due to their role as a readily available energy source. During intense physical activity, the body relies heavily on glucose, which is derived from carbohydrates, because it can be quickly broken down to provide ATP (adenosine triphosphate), the energy currency of the cell. This rapid energy release is crucial for activities such as sprinting, weightlifting, or any form of exercise that demands quick bursts of energy.

In contrast, fats are a more efficient source of energy during low to moderate-intensity exercise where oxygen supply is more adequate for their metabolism. Proteins, while important for muscle repair and growth, are not a primary fuel source for exercise, especially not for high-intensity efforts. Fiber, on the other hand, aids in digestion and does not serve as a direct energy source. Thus, carbohydrates stand out as the key macronutrient for fueling high-intensity physical activity effectively.