Complete vs. Incomplete Proteins

Eating enough protein per day is important for keeping our bodies functioning efficiently. Without it, everything from our immune systems, lean muscle to our hair can take a hit. But when it comes down to it, the type of protein you eat matters!

Protein can be divided into two categories, complete and incomplete, based on its CHEMICAL structure. Knowing the difference between complete and incomplete proteins will help you figure out how to get the right mix of this essential macronutrient.

First, the basics: Protein is made up of amino acids, some of which the human body can make on its own, and others we need to get from food.

Amino acids are organic compounds that combine to form protein. They’re usually referred to as the “building blocks” of protein. There are 20 different amino acids in the body—11 are nonessential, or those our body can make, and nine are essential, or those we cannot make and need to get from food.

Here’s that list of nine amino acids we can only get from the protein we eat: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Every amino acid plays an important role in building protein structures in the body. This example includes enzymes to help digest food, antibodies to keep the immune system strong, muscles and hair, and red blood cells. Unlike fat and carbohydrates, our bodies can’t store amino acids for future use, so we pretty much have to consume a little bit of each of them every single day.

Some of the protein sources we eat contain all nine essential amino acids; others are lacking.

Complete proteins are those that have all nine essential amino acids that our bodies cannot naturally make, whereas incomplete protein sources may have a few of the nine, but not all of them.

For the most part, animal protein is complete and plant protein is incomplete, though there are some exceptions. The general rule is that animal foods—beef, chicken, fish, turkey, QUINOA, eggs, and dairy—are complete, while plant foods—nuts, seeds, rice, beans, and grains—are incomplete. Here are plant sources of complete protein: soy, quinoa, seitan, and buckwheat.

If you eat a variety of healthy foods each day, chances are you’re getting all the right amino acids without trying—even if you’re vegan.

Meat, dairy, fish, and eggs are the most obvious sources of complete proteins.

If you are vegan and do not eat those foods, you can use “COMPLEMENTARY FOODS” along with edamame and quinoa to get complete sources of protein. Complementing is when you take two incomplete plant proteins and put them together to receive all nine essential amino acids. For example: it is popular to combine rice and beans, hummus and pita, a peanut butter sandwich on whole grain rice cakes, sprouted low sugar cereal or oats with almond milk, and lentil soup with flax crackers.

To know exactly which amino acids you’re getting from different foods, you can use the USDA Food Composition Databases. But experts don’t think that’s necessary—simply mixing a variety of sources throughout the day (grains, legumes, nuts) should do the trick.

Experts used to think that you had to combine two complementary protein sources in one meal for this to work, but that’s been found to be untrue. The new research says it doesn’t necessarily have to be all in the same meal, just over 24 hours, to combine to make a protein complete.

For easy reference, here are some of the best sources of complete protein:

1. Chicken

2. Turkey

3. Steak

4. Pork

5. Eggs

6. Milk

7. Cheese, white

8. Yogurt: Greek, German or Icelandic

9. Fish

10. Tofu or Tempeh

11. Quinoa

12. Seitan

13. Buckwheat

14. Brown rice and black beans

15. Hummus and 1 slice pita bread

16. Peanut butter sandwich on whole grain bread

17. Lentil soup with whole grain bread

18. Stir-fry with peanut sauce and pine nuts

19. Pesto and pine nuts

20. Whole Grain low sugar cereal with almond milk

21. Nut mix (with unsweetened dried cranberries or mulberries)