Are Pinto Beans a Complete Protein?

Beans aren't like many other protein-rich foods: According to the U.S. Department of Agriculture, they have enough fiber, vitamins and minerals to be considered a vegetable and rich source of complex carbohydrates while still being high enough in protein to act as a substitute for meat, poultry or seafood. Eating pinto beans, which are the most commonly consumed variety of bean in the United States, helps to fulfill your protein requirement while keeping your total fat, saturated fat and cholesterol intake low.

Dried pinto beans in a glass bowl. (Image: lsantilli/iStock/Getty Images)

Protein Content of Pinto Beans

A 1/4-cup serving of cooked pinto beans contains 3.85 grams of protein. This is not complete protein, however. Pinto beans -- like all other beans besides soy beans -- have a high concentration of many of the amino acids your body needs in order to synthesize vital protein-based compounds, such as tryptophan, isoleucine, valine and histidine, but they do not have enough of the other amino acids to supply your body's total protein needs.

Making Complete Protein

To make the protein that you receive from pinto beans complete, you'll need to ensure that your diet includes rich sources of the amino acids that pinto beans lack. If you regularly consume animal-based products like meat, poultry, fish, shellfish or dairy products, or you eat soy or quinoa -- the only two plant-based sources of complete protein -- you already have complete proteins in your meals. If you do not, however, you can get the amino acids pinto beans don't have by eating a variety of whole grains, nuts, seeds and produce throughout the day.

Expert Recommendations

The USDA says that women need between 5 to 5 1/2 ounces of high-protein foods each day, while men need around 6 to 6 1/2 ounces. A 1/4-cup serving of cooked pinto beans counts as 1 ounce of protein and is equivalent to the protein content of one egg, 1/2 ounce of nuts or seeds and 1 ounce of cooked meat, poultry or seafood. Whenever possible, the Harvard School of Public Health advises consuming cooked beans like pintos instead of red meat or processed meat products.

Fitting Pinto Beans into Your Diet

You don't need to eat pinto beans in the same meal as a complementary source of protein in order to get all the amino acids, assures the Centers of Disease Control and Prevention. You just need to eat both within the same day. Some traditional combinations are reliably tasty as well as healthy, however. Try a whole-wheat pinto bean burrito or saute cooked pinto beans with tomatoes, herbs and spices and serve them on brown rice. Mix pinto beans into cooked bulgur or barley for a grain salad or stir them into vegetable soup.