First things first: When we talk about eating more protein, we're actually talking about eating more proteins — plural.
Proteins are large, complex molecular chains made up of amino acids, the organic compounds the body needs to do things like grow, break down food, and repair muscle tissue. There are 20 different types of amino acids that combine to make a protein, including nine "essential" amino acids that your body needs to function but can't make on its own.
When you eat a protein-rich food, it's broken down to its component amino acids during digestion, and those amino acids get to work supporting your immune system, bone health, hormone signaling, and more. Think of proteins as the building blocks of your body.