What two foods can you pair for a complete protein?

October 6, 2025 •

5 min read

Historically, nutrition advice suggested that plant-based eaters needed to combine specific foods at every meal to form a complete protein, a concept that is now considered a myth by most dietitians. However, understanding what two foods can you pair for a complete protein can still be a helpful, easy way to ensure a well-rounded diet.

Quick Summary

This guide explains the concept of complementary proteins, where two incomplete plant-based protein sources are paired to provide all essential amino acids. It covers classic combinations like rice and beans, debunks the myth of needing to combine proteins in a single meal, and offers practical examples for daily meal planning.

Key Points

Combine Grains and Legumes: Classic pairings like rice and beans or peanut butter on whole-wheat toast create a complete protein because grains lack lysine and legumes lack methionine.
Protein Combining in a Single Meal is a Myth: You do not need to combine complementary proteins in one meal; a varied diet over the course of a day is sufficient for your body to gather all essential amino acids.
Variety is Crucial: Focus on eating a diverse range of plant-based foods, including legumes, grains, nuts, and seeds, to ensure all nine essential amino acids are consumed daily.
Some Plant Foods are Naturally Complete: Several plant-based foods, such as quinoa, soy (tofu, edamame), and hemp seeds, contain all nine essential amino acids on their own.
The Body Maintains an Amino Acid Pool: Your body recycles and stores amino acids from foods eaten throughout the day, allowing it to create complete proteins as needed, regardless of when they were consumed.
Embrace Flexibility: The modern dietary approach emphasizes flexible, varied, and enjoyable eating rather than rigid rules about combining foods.

Understanding the 'Complete Protein' Concept

To understand why certain food pairings work, it's essential to know what a complete protein is. Proteins are large molecules made up of smaller units called amino acids. The human body requires 20 different amino acids to function, nine of which are considered "essential" because the body cannot produce them on its own. Complete proteins are food sources that contain all nine of these essential amino acids in sufficient quantities. Animal products like meat, eggs, and dairy are classic examples, but several plant-based foods, such as soy (tofu, tempeh, edamame), quinoa, and hemp seeds, are also complete proteins.

Most other plant foods are considered "incomplete" because they are low in or missing one or more essential amino acids. For example, grains are often low in lysine, while legumes are low in methionine. The concept of complementary proteins was developed to address this, suggesting that by pairing two incomplete protein sources, you could create a complete protein profile. While this was once a rigid rule for vegetarians and vegans, modern nutrition science confirms that as long as a variety of plant proteins are consumed throughout the day, the body can assemble the necessary amino acids. You do not need to combine them in a single meal.

Classic Pairings: Grains and Legumes

The most widely known examples of complete protein pairings involve combining grains and legumes. This combination is a staple in cuisines around the world and for good reason: legumes provide the lysine that grains lack, while grains provide the methionine that legumes need.

Rice and Beans: This is the quintessential complementary protein pairing, found in dishes from Latin American gallo pinto to Creole red beans and rice. The black beans (or other legumes) and brown rice perfectly complement each other's amino acid profiles.
Peanut Butter on Whole Wheat Toast: A quick and easy pairing, this combines the legumes (peanuts) with a whole grain (bread) to create a satisfying and complete protein snack.
Hummus and Pita Bread: Hummus is made from chickpeas (a legume) and tahini (a paste from sesame seeds), while pita is a grain. This combination of legumes and grains creates a complete protein in a single, delicious dish.
Corn Tortillas and Black Beans: A traditional Mexican combination, this pairs the corn (a grain) with black beans (legumes) for a complete meal, often seen in tacos or burritos.

More Complementary Combinations

Beyond the classic grain-and-legume pairings, other food groups also work well together to create a complete protein profile. Combining legumes with nuts and seeds is another powerful strategy.

Lentil Soup with Almonds: A hearty lentil soup (legumes) topped with a sprinkle of almonds (nuts) provides a full spectrum of amino acids.
Salad with Chickpeas and Sunflower Seeds: This vibrant and fresh meal combines chickpeas (legumes) and sunflower seeds (seeds) to provide a complete protein source.
Oatmeal with Pumpkin Seeds: A simple breakfast that pairs the grains in the oatmeal with protein-rich pumpkin seeds.
Pasta with Peas: A comforting and simple pairing, this combines the grains in the pasta with the legumes (peas) for a complete protein.

Understanding the Complementary Protein Myth

For many years, the idea of "protein combining" was heavily emphasized, largely due to Frances Moore Lappé's 1971 book, Diet for a Small Planet. Her work, though influential, created a widespread misconception that incomplete proteins had to be consumed together in the same meal. This led to unnecessary anxiety and complication for many people following plant-based diets. Health organizations and dietitians have since corrected this misconception. The human body is remarkably efficient at using the amino acids from a variety of foods eaten throughout the day to meet its needs. The body maintains a pool of amino acids, which it draws from as needed to build and repair tissues. As long as you consume a varied and balanced diet, you do not need to meticulously combine proteins at every meal. This debunking allows for much more flexibility and enjoyment in plant-based eating, moving the focus from strict combinations to overall dietary diversity.

Comparison of Plant vs. Animal Protein


Feature	Plant-Based Protein	Animal-Based Protein
Completeness	Most sources are incomplete, but can be combined. Some are naturally complete (soy, quinoa).	All sources are complete proteins.
Essential Amino Acids	Variety of sources required to provide all nine essential amino acids over the course of a day.	All nine essential amino acids are provided in a single source.
Nutrient Profile	High in fiber, vitamins, minerals, and phytochemicals. Often lower in saturated fat.	Can be high in saturated fat and cholesterol. Does not contain dietary fiber.
Health Benefits	Associated with lower rates of heart disease, diabetes, and certain cancers.	Associated with a higher intake of saturated fat and cholesterol, but depends on the cut and source.
Digestibility	Can be slightly lower, but the difference is generally not significant for overall health.	Generally higher.
Environmental Impact	Generally lower environmental impact.	Higher environmental impact.

Conclusion: Flexibility is Key

The need to constantly monitor and combine foods to form a complete protein is an outdated dietary guideline. While classic pairings like rice and beans or peanut butter on toast are still excellent, nutritionally sound choices, the modern understanding of nutrition emphasizes the importance of a varied diet over a 24-hour period. For those on a plant-based diet, simply eating a diverse range of plant foods—including a mix of legumes, grains, nuts, and seeds—is enough to ensure all essential amino acids are consumed. This flexibility makes it easier and more enjoyable to eat a healthy, well-rounded diet, whether you're a vegetarian, vegan, or simply looking to add more plant-based meals to your week. Focus on variety, listen to your body, and enjoy the delicious combinations that plant-based foods offer.

A Note on Protein Digestion: For more in-depth information on protein absorption and the efficiency of plant-based diets, the American Journal of Clinical Nutrition provides studies that show that both plant and animal proteins can equally benefit muscle health.(https://www.ncbi.nlm.nih.gov/pubmed/28179224)

Frequently Asked Questions

A complete protein is a food source that contains all nine of the essential amino acids that the human body cannot produce on its own. Examples include meat, eggs, dairy, soy, quinoa, and hemp seeds.

No, you do not need to eat complementary proteins in the same meal. The old guideline is considered outdated. The human body maintains a pool of amino acids and will draw from various food sources consumed throughout the day to meet its protein needs.

The most well-known example is rice and beans. This combination works because the amino acid that legumes (like beans) are low in (methionine) is plentiful in grains (like rice), and vice versa.

Yes. A well-planned and varied vegan or vegetarian diet can provide all the necessary essential amino acids. By eating a mix of legumes, grains, nuts, and seeds throughout the day, your body will have everything it needs.

Yes, several plant foods are complete proteins, meaning they contain all nine essential amino acids on their own. Examples include soy products (tofu, tempeh), quinoa, hemp seeds, and buckwheat.

Essential amino acids are the nine amino acids that your body cannot produce, so they must be obtained from your diet. Non-essential amino acids are those that your body can produce on its own.

Nuts and seeds, like grains, provide the methionine and other essential amino acids that are limited in legumes. Pairing them in dishes like a salad with chickpeas and sunflower seeds or a lentil bowl with almonds ensures a complete protein profile.