Which of the following provides the most energy during prolonged exercise?

The selection of fats as the primary source of energy during prolonged exercise is supported by their high energy density and the role they play in endurance activities. Fats are the most efficient fuel source for long-duration exercise because they provide a significant amount of energy per gram compared to carbohydrates and proteins.

During prolonged activities, such as marathon running or long-distance cycling, the body's carbohydrate stores (glycogen) become depleted. As a result, the body shifts to utilizing fat stores for energy, which are abundant and can sustain energy needs for extended periods. Aerobic metabolism, which is the pathway the body uses most efficiently for prolonged exercise, favors fat oxidation as it can provide ATP (adenosine triphosphate) over longer durations without leading to an accumulation of lactate associated with exhaustive exercise.

While carbohydrates are essential for quick bursts of energy and can be used effectively during both high-intensity and moderate-intensity exercise, their stores are limited. Proteins primarily serve as a building block for muscle repair and growth and are not a primary energy source during exercise. Minerals, while critical for various bodily functions and energy production processes, do not provide energy by themselves.

Thus, fat stands out as the most critical source of energy during prolonged exercise, particularly when exercise