Here's why:

* Building Blocks: Proteins are made up of amino acids, which are the building blocks for all cells and tissues in the body.

* Structure and Function: Proteins provide structure to tissues like muscles, skin, and bones. They also play vital roles in a wide range of bodily functions, including:

* Enzyme activity (catalyzing chemical reactions)

* Hormone production (regulating bodily processes)

* Immune system function (fighting infections)

* Transport of molecules (carrying oxygen and other substances)

While other substances like carbohydrates and fats are essential for energy and other functions, protein is the primary substance responsible for building and repairing body tissues.