What is the primary function of proteins in the body?

The primary function of proteins in the body is to build and repair tissues. Proteins are made up of amino acids, which serve as the building blocks for the body's cells, muscles, skin, and organs. During periods of growth, healing, or physical stress, the body relies on protein to synthesize new tissues and repair damaged ones. This includes muscle tissue after exercise, skin after wounds, and various cellular structures throughout the body.

While proteins can contribute to energy needs, particularly if carbohydrates and fats are not sufficient, their main role is not energy provision but rather structural and functional support. The other options highlight functions that proteins may influence or interact with, but they are not the primary role of proteins in the body's overall physiology. For example, regulating body temperature is mainly the role of other systems in the body, and producing glucose from fat is a process primarily associated with metabolic pathways involving carbohydrates and fats.