What primary function do carbohydrates serve in the body?

Carbohydrates serve as a primary source of energy for the body, particularly for the brain and other cells. When consumed, carbohydrates are broken down into glucose, which is utilized by cells to produce the energy required for various bodily functions. The brain, in particular, relies heavily on glucose as its main energy source because it is unable to store energy in the form of fat and needs a constant supply of glucose to function optimally. This is why a carbohydrate-rich diet can be critical for overall cognitive performance and energy levels.

Other functions mentioned in the choices, such as providing insulation or regulating blood pressure, do not accurately describe the primary role of carbohydrates. While fibers from carbohydrates can aid digestion, this is secondary to their main function of providing energy. Similarly, regulating blood pressure and cholesterol is more related to the roles of fats, proteins, and other nutrients rather than carbohydrates.