Which nutrient is considered a primary source of energy for the body during physical activity?

Carbohydrates are considered a primary source of energy for the body during physical activity because they are quickly and efficiently metabolized to provide fuel for muscles. When engaged in activities, particularly those that require bursts of energy or prolonged exertion, the body breaks down carbohydrates into glucose, which can then be used immediately for energy or stored in the muscles and liver as glycogen for later use. This process is essential, especially during high-intensity workouts, where energy demands are significant.

Fats, while also a source of energy, are utilized more effectively during lower-intensity activities or endurance exercises. Vitamins, on the other hand, do not provide energy directly; rather, they play supportive roles in various metabolic processes. Proteins, while crucial for repairing and building tissues, are not the body's preferred energy source during physical activity, as they are primarily used for muscle repair and growth rather than energy production. Thus, carbohydrates hold the key role as the body's primary fuel source during physical exertion.