Incomplete Protein

Understanding incomplete protein

It is easy to understand the difference between complete protein and incomplete protein, if you know that proteins are made up of building blocks called “amino acids.” There are about 20 common amino acids. Nine of them are considered “essential” because the body cannot make them, and therefore, they must be supplied by your diet. If your diet does not contain enough of these essential amino acids, you may suffer from protein deficiency.

Not all proteins have all of the amino acids

Foods that contain all of the essential amino acids are called “complete proteins.” For the most part, these protein foods come from animals. Plant foods do not, as a rule, have complete proteins, but by eating combinations of plant foods, called “complementary proteins,” you can obtain a complete protein.

For example, when you eat Mexican foods, such as refried beans with rice, you are creating a complete protein. The beans and rice complement each other, because each has some of the building blocks and together, they provide all of the essential amino acids. It is generally believed by food scientists that it is not necessary to eat these complementary proteins at the same meal.


Here is a list of complementary proteins, that is, proteins that when combined become complete.

Click here for a printable copy of this list.

Complementary Protein Foods

Nuts/Seeds... with Dairy

Nuts/Seeds... with Legumes

Beans/Peas/ Lentils ... with Nuts 

Beans/Peas and/Lentils ... with Grains

Beans/Peas/Lentils ... with Seeds

Beans/Peas/Lentils ... with Dairy

Grains... with Dairy

Dairy... with Nuts/Seeds and Beans/Peas/Lentils


Protein deficiency more common in less developed countries

Since most foods have at least some protein and many foods have significant protein, if you eat two to three healthy meals each day, you are probably getting enough protein. However, if you live in a less developed country, protein deficiency may be a serious concern. Many in poor countries struggle to meet the minimum requirements for protein in their diet.


Vegetarians should also pay attention to protein consumption and include complementary proteins in their daily diet.

What if I don’t get enough?

You have probably figured out by now that protein is an important nutrient. For that reason, if there is not enough protein in your diet, it will have a noticeable effect on your health, from being susceptible to infections to actually wasting away.

Severe protein deficiency is most often associated with starvation and malnutrition and is a major cause for concern in developing nations, especially among children. In developed countries, severe protein deficiency is mostly associated with those in extreme poverty or those suffering with eating disorders, such as anorexia nervosa. Severe protein deficiency can lead to death.


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