How Protein Fits in a Healthy Diet

Proteins

Verywell / Alexandra Shytsman

There are three general classifications for food: protein, fat, and carbohydrate. This article is about protein. We'll talk about what it is, why you need it, how to get it, and how much you need in order to be healthy.

Why We Need Protein

Before we get into the details of what protein is, let's get motivated by appreciating what protein does. Our bodies use protein to build just about everything. Skin, hair, muscles, organs, even the hemoglobin in your blood is made of protein.

And the list goes on: The enzymes that break down food and spark chemical reactions in the body are proteins. Our immune systems depend on protein to make antibodies. Protein molecules aid the transfer of messages between the neurotransmitters in our brains. And many hormones, including insulin and other metabolism-regulating hormones, are proteins as well.

If you're thinking, where's the protein? Let me at it. But before we go there, we should sneak in a little bit of science about what protein actually is. Protein molecules are made of smaller molecules called amino acids. There are twenty naturally occurring amino acids. Some names you might be familiar with are lysine, glutamine, and tryptophan. When you eat foods that contain protein, your body breaks those proteins down and reassembles the amino acids to create the protein structures it wants to make.

The human body can synthesize eleven of the amino acids it needs. However, nine amino acids are called essential amino acids because they must be taken in from food.

When a single food provides all nine essential amino acids, it is called a complete protein.

Many foods contain high levels of some amino acids and not others. In that case, foods have to be combined in order to provide all nine amino acids. When foods go together to create a complete protein profile, they are called complementary proteins. Foods don't necessarily have to be consumed at the same time, however.

Sources of Protein

Most people think of meat when they think of protein. And that's correct. Meat from land animals, fish, and fowl are all high-protein foods. However, nuts, seeds, beans, and dairy products are high-protein foods as well. And whole grains such as brown rice, whole wheat, quinoa, barley and amaranth, and some vegetables, like avocados and sprouts, can be significant sources of protein too.

Meat, dairy, and eggs are complete proteins. Most grains, nuts, seeds, and vegetables have to be combined to get a complete protein.

Rice and beans or corn and beans are famous examples of complementary proteins. It is worth noting that you don't have to get all essential amino acids in one meal. Amino acids are not stored by the body, but they do stay available long enough to be used and combined throughout a day. With so many sources of protein, eating a healthy, varied diet generally provides enough amino acids for the average person—even if they exercise.

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6 Tips for Getting More Protein in Your Diet

How Much Protein You Need

People do have different protein requirements depending on their age, their size, their levels of activity and health. However, those requirements are not as high and don't vary as much, as some of the popular hype around protein might lead one to believe.

Current dietary guidelines set forth by the U.S. Department of Agriculture (USDA) recommend that adult women consume 46 grams of protein per day or 10%–30% of your total calories. For adult men, 56 grams of protein is recommended or 10%–30% of your total calories.

The USDA offers the following guidelines as to what serving sizes equal an ounce of protein: In general, 1 ounce of meat, poultry or fish, ¼ cup cooked beans, 1 egg, 1 tablespoon of peanut butter, or ½ ounce of nuts or seeds can be considered as 1 ounce equivalent from the Protein Foods Group.

Protein and Exercise

Those who exercise need more protein, but sometimes the amount is less than you might assume. For example, for endurance athletes the recommendation ranges from 0.8 to 1.2–1.4 grams of protein per kilogram of body weight per day.

It is important to know that protein is not the body's preferred fuel for a workout—carbohydrate is. Protein is important after a workout to repair and build muscle. But it doesn't take much more protein to do that—an ounce or two for most people who exercise at moderate intensity.

For those engaged in intensive strength training or for endurance athletes, the recommendation is at most twice the amount of protein the average person needs. 

Protein Supplements

Another way to get protein in your diet is through supplements. Amino acids can be found in pill form, individually and in complete protein combinations. More popular, however, are powdered proteins sourced from any variety of foods. Powdered whey (from milk) protein is very popular, as is soy protein.

There are also protein powders made from peas, rice, sprouts, even hemp. Many people find supplemental protein easy to digest and enjoy protein powders blended in health shakes as a way to get nutrition without bulk in the belly. 

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8 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. U.S. National Library of Medicine. National Institutes of Health. National Center for Biotechnology Information. Amino Acid Explorer.

  3. U.S. National Library of Medicine. MedlinePlus. Amino acids. Updated May 25, 2021.

  4. Gordon B. EatRight.org. Academy of Nutrition and Dietetics. How Much Protein Should I Eat? Updated October 2020.

  5. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2020–2025 Dietary Guidelines for Americans. Ninth Edition. December 2020.

  6. U.S. Department of Agriculture. MyPlate.gov. Protein Foods. Dietary Guidelines for Americans, 2020–2025.

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