Final answer:
Proteins are essential for structural components, growth, maintenance, and hormone synthesis, but 'providing energy' is not their primary role; carbohydrates and fats serve as the main energy sources.
Step-by-step explanation:
As asked here, the option that is NOT a major function of protein in the human body is 'Providing energy to the body'. Proteins have many essential roles such as being a structural component of cells, contributing to growth and maintenance of new tissue, as well as the synthesis of hormones.
However, while proteins can be used as a metabolic fuel source when necessary, it is not their primary function.