Protein is one of a complex group of molecules that do all kinds of jobs in your body. They make up your hair, nails, bones, and muscles. Protein gives tissues and organs their shape and also helps them work the way they should. In short, protein is one of the building blocks that make you into who you are.
Protein isn’t your body’s first — or even second — choice for getting energy. That role is reserved for carbohydrates and fats. But when you’re running low on calories, or if you’re a serious athlete, thank protein for keeping you going past the point of normal energy stores.
You need protein to keep up the size and shape of your muscles. As you lose weight, protein prevents you from losing muscle at the same time. If you lift weights for strength, protein is the key to building more muscle.