What is the primary function of carbohydrates in the diet?

The primary function of carbohydrates in the diet is to provide energy for daily activities and exercise. Carbohydrates are one of the body's most important sources of energy, particularly for the brain and during physical activity. They are broken down into glucose, which is then used by the body's cells to fuel various functions, from simple tasks like walking to more intense activities such as running or lifting weights.

In addition to being a quick source of energy, carbohydrates are also vital for maintaining optimal body function. Complex carbohydrates, found in foods like whole grains, fruits, and vegetables, are not only energy-rich but also provide essential nutrients and dietary fiber that support overall health.

The other options, while they describe important functions of the body, do not represent the primary role of carbohydrates. Regulating body temperature, supporting immune function, and enhancing nutrient absorption involve other macronutrients and physiological processes. For instance, proteins and fats play more significant roles in immune function and temperature regulation, while certain fibers can aid nutrient absorption, but they are not classified under carbohydrates in terms of primary energy function.