Why do we need to eat protein?

Just like vitamins, our bodies need protein in our diets to survive. We can only create some of the building blocks needed for growth and maintenance. The rest needs to come from protein in our food.

Professionally Reviewed by Charles Li, MD

1. Your Body Needs Protein

Just like vitamins, our bodies need protein in our diets to survive. We can only create some of the building blocks needed for growth and maintenance. The rest needs to come from protein in our food.

2. Proteins = Calories

Just like bread and butter, proteins are a key source of calories for our bodies. They provide energy to keep us going.

3. Proteins Build Muscles

Research has shown again and again that eating lots of protein helps build muscle mass.

1. Amino Acids

Protein Building Blocks

While your body doesn't necessarily re-use proteins, it does re-use the building blocks of proteins in food to build proteins in your body.

It's like taking an old lego creation and using the bricks to build a new one.

Of the 20 amino acids our body needs, our bodies can build 11 by itself.

This of course means that we need to get the other 9 from our diets. By eating enough protein, we ensure that our bodies get enough amino acids to build and maintain our own organs and tissue.

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fact sheet

Amino Acids

Function

Protein Building Blocks

Sources

Food, biosynthesis

Key Precursor

glucose

Amino acids are the building blocks for proteins. Your body can create many amino acids through its own chemical reactions. However, we still need to get protein from our diets for the amino acids that we cannot synthesize ourselves.

2. Calories

Proteins Provide Energy

Proteins are actually a great source of energy. It's one of the key macronutrients along with fats and carbohydrates.

By eating protein, we provide much-needed energy to our body, similar to eating a Snicker's candy bar.

When our body doesn't have enough carbohydrates or fat to burn, it can use protein for energy. However, in general, protein contains fewer calories than fat.

On the other hand, if you're trying to lose weight, eating protein instead of fat may be a good thing for your diet.

Comparison of Proteins, Carbohydrates, and Fats. Proteins provide 4 calories per gram, similar to carbohydrates. Fats have the highest energy density at 9 calories per gram.

3. Muscle Building

Proteins Build Muscles

Your muscles are built from protein. They are particularly sensitive to how much protein you eat.

Studies have shown that high protein diets can help with muscle building.

Data from 49 studies found that those who ate supplemental protein lifted more weight, gained more muscle mass, and developed larger muscles compared to those who did not.

Individuals on a high protein diet lifted over 5 pounds more. Eating more protein leads to more fat-free body mass. Those on high protein diets typically showed a significant increase in muscle size.