What Is Protein?

Proteins are large molecules that help build, repair, and maintain tissues. They’re the foundation of your muscles, bones, skin, organs, and even your hair and nails.

Proteins are made up of smaller parts called amino acids.

There are 20 amino acids total
9 are essential (you must get them from food)
11 are nonessential (your body can make them)

Think of amino acids like alphabet letters—you can combine them in countless ways to “spell” different proteins your body needs.

Protein in Food

Protein comes from both animal and plant sources:

Animal-based: chicken, fish, eggs, beef, yogurt, cheese
Plant-based: beans, lentils, tofu, tempeh, nuts, seeds, whole grains

Fun fact: plant proteins can be combined (like beans + rice) to cover all the essential amino acids.

a heavy protein dish — Photo by LikeMeat on Unsplash

Why Protein Matters

Helps your body repair damage
Supports growth and development
Maintains muscle and bone strength
Regulates pH and fluid balance
Helps you feel satisfied after meals

Too Much or Too Little?

Too much: If you eat far beyond what your body needs, extra calories may be stored as fat, and you also might be missing out on other nutrients if you’re so focused on protein (see FIBER!)
Too little: Can lead to muscle loss, bone weakness, fatigue, and impaired recovery

What Happens After You Eat Protein?

When you eat protein—your body gets right to work:

Digestion begins in the stomach.
Stomach acid and enzymes (like pepsin) start breaking down protein into smaller chains of amino acids
In the small intestine, more enzymes continue the process until proteins are broken down into individual amino acids
Amino acids enter your bloodstream, traveling to where your body needs them most
Inside your cells, amino acids are “rebuilt” into new proteins that serve specific purposes—like repairing muscle fibers after exercise, building hormones and enzymes, or supporting your immune system

Any extra amino acids can be:

Used for energy (if needed)
Converted into fat or glucose if your body has more than it needs
Converted into waste

Why This Matters

Protein isn’t just for athletes—it’s essential for everyone. Without enough, you may feel tired, lose muscle, or struggle to recover from injuries. Too much won’t usually harm you, but eating far beyond what your body needs could lead to weight gain and put stress on your kidneys. I should note, that if you have any kidney issues than eating in excess will lead to extra stress on the kidneys and unfortunately be harmful for you. You should work with a healthcare professional if you fit into this category.

The Bottom Line

Protein is essential, but you don’t need to overthink it. Include a protein source at each meal/snacks, mix up your choices, and you’ll give your body the building blocks it needs to stay strong.

Nutrition 101: Protein