What two vegetables make a complete protein? Understanding the nutrition diet basics

October 4, 2025 •

4 min read

Approximately 25% of 25 to 34-year-olds in the U.S. now identify as vegetarian or vegan, increasing the interest in how to get complete proteins from plant-based sources. The key is understanding that while few single vegetables are complete, strategically combining them or pairing them with other plant foods can easily answer the question, "What two vegetables make a complete protein?".

Quick Summary

This guide explains the concept of complete and incomplete proteins, focusing on how plant-based foods can be combined to form a complete amino acid profile. It debunks common myths about vegan diets and protein, highlighting popular food pairings and naturally complete plant sources.

Key Points

Combine Legumes and Grains: The classic complementary pairing is a legume (like beans or lentils) with a grain (like rice or whole-wheat bread).
Variety, Not Timing: You don't need to eat complementary proteins in the same meal; consuming a variety of plant foods over the course of a day is sufficient for your body to combine the amino acids.
Naturally Complete Plant Proteins: Foods like soy (tofu, tempeh), quinoa, and hemp seeds are naturally complete proteins and do not require pairing.
Popular Combinations: Classic examples include rice and beans, hummus with pita bread, and peanut butter on whole-wheat toast.
Holistic Health Benefits: A varied plant-based diet rich in protein also provides increased fiber and other nutrients, which can help reduce the risk of chronic diseases.
Focus on Whole Foods: Prioritizing whole, unprocessed plant foods ensures a higher intake of beneficial nutrients and avoids the pitfalls of relying on ultra-processed alternatives.

The Science Behind Complete Protein

Protein is a crucial macronutrient made up of smaller units called amino acids. The human body requires 20 different amino acids, nine of which are considered "essential" because they cannot be synthesized by the body and must be obtained from food. A "complete protein" contains all nine essential amino acids in sufficient quantities. While animal products like meat, eggs, and dairy are classic examples of complete proteins, many plant foods are considered "incomplete" because they are low in one or more of these essential amino acids. However, by combining different plant sources, a person can create a complete amino acid profile throughout the day.

Combining Incomplete Plant Proteins

For decades, it was believed that complementary proteins had to be consumed in the same meal to be effective. This has since been debunked, as the body can pool and store amino acids throughout the day to form complete proteins. The secret to creating a complete protein from vegetables lies in pairing a legume with a grain, which is a method employed by many traditional cuisines worldwide.

Here are some classic examples of plant-based complementary proteins:

Legumes + Grains: Legumes, including beans, peas, and lentils, are rich in the amino acid lysine but often low in methionine. Grains, such as rice and wheat, are typically low in lysine but high in methionine. Combining them creates a complete protein. A prime example is the classic combination of rice and beans.
Legumes + Nuts or Seeds: This pairing also works well. For instance, hummus, made from chickpeas (a legume), is a perfect complement to pita bread (a grain). A peanut butter sandwich on whole-wheat bread is another well-known example.
Combining Vegetables: While less common than grain-and-legume pairings, combining certain vegetables with other plant foods can also create a complete protein. For example, a chickpea and spinach curry provides a robust amino acid profile when served with rice. Another combination could be a salad of chickpeas and sunflower seeds.

The Role of Naturally Complete Plant Proteins

Certain plant foods are naturally complete proteins on their own, making it easy to meet daily protein needs without any complex combinations. These options are excellent staples for anyone following a plant-based diet.

Some prominent examples include:

Soy products: Tofu, tempeh, and edamame are all made from soybeans and are excellent sources of complete protein. Tofu is made from condensed soy milk, tempeh is a fermented soy product, and edamame are immature soybeans.
Quinoa: A "pseudocereal" that is technically a seed, quinoa is a gluten-free grain that provides all nine essential amino acids.
Hemp seeds: These tiny, nutrient-dense seeds contain an impressive 10 grams of complete protein in just three tablespoons.
Chia seeds: Another excellent seed-based option, chia seeds offer a complete protein and can be added to many dishes.
Amaranth: An ancient grain, amaranth is also a complete protein.

Popular Complete Protein Pairings


Food Combination	Protein Source Breakdown	Benefits	Example Meal
Rice and Beans	Rice (low in lysine) + Beans/Lentils (low in methionine)	Classic and affordable staple found in many cultures. High in fiber.	Black bean and rice burrito bowl.
Hummus and Pita Bread	Chickpeas (low in methionine) + Whole-Wheat Pita (low in lysine)	A convenient and healthy snack or appetizer. Rich in fiber and healthy fats.	Pita with hummus and cucumber slices.
Peanut Butter on Toast	Peanuts (legume, low in methionine) + Whole-Wheat Bread (grain, low in lysine)	A simple, classic breakfast or snack. Provides healthy fats and protein.	Natural peanut butter on whole grain toast.
Quinoa and Edamame	Quinoa (complete protein) + Edamame (complete protein)	A nutrient powerhouse with two complete protein sources. High in fiber and various minerals.	Quinoa and edamame salad with a light vinaigrette.
Lentils and Nuts	Lentils (low in methionine) + Nuts (low in lysine)	A robust and savory combination. Adds crunch and healthy fats to dishes.	Lentil soup topped with crushed almonds or walnuts.
Tofu and Vegetables	Tofu (complete protein) + Vegetables (various amino acids)	A versatile and flavorful meal base. Easy to season to your liking.	Tofu and broccoli stir-fry with brown rice.

Creating a Balanced Nutrition Diet

Achieving complete protein status with a vegan or vegetarian diet is a matter of variety, not complexity. By eating a diverse range of plant foods throughout the day, your body efficiently combines the amino acids from different sources to build and repair tissues. This approach offers numerous health benefits beyond just protein intake, such as higher fiber and lower saturated fat consumption. It also emphasizes whole foods over reliance on single sources or highly processed alternatives, contributing to a more sustainable and wholesome diet.

For example, a person could have a breakfast of oatmeal with nuts and seeds, a lunch with a chickpea salad sandwich on whole-wheat bread, and a dinner of rice and beans. The amino acids from each meal contribute to the body's overall protein needs. It is far more important to focus on overall dietary diversity than to stress over the precise combination of foods in every single meal. Consulting with a registered dietitian is a great way to receive personalized guidance for optimal nutrition.

Conclusion

While the concept of needing specific pairings of vegetables to make a complete protein was once a major focus, modern nutritional science confirms that a varied plant-based diet naturally provides all essential amino acids throughout the day. The simplest answer to what two vegetables make a complete protein is a combination of legumes and grains, such as beans and rice. However, with many naturally complete plant proteins now widely available, including soy products, quinoa, and hemp seeds, meeting protein needs on a plant-based diet is more accessible and delicious than ever. The ultimate goal for optimal nutrition is to embrace a wide variety of whole, unprocessed plant foods to create a balanced diet rich in protein, fiber, vitamins, and minerals.

Frequently Asked Questions

A complete protein contains all nine essential amino acids that the human body cannot produce on its own. An incomplete protein is a food source that is low in one or more of these essential amino acids.

No, this is a common myth. The human body can pool amino acids throughout the day from various food sources to create complete proteins, so you only need to ensure variety in your diet.

While most individual vegetables are not complete proteins, some plant sources like soybeans (edamame) are. Others, like peas, can contribute significantly to your overall amino acid intake.

Good examples include rice and beans, hummus and pita bread, and peanut butter on whole-wheat bread.

Quinoa is a seed from a flowering plant, though it is often prepared and used like a grain. It is a source of complete protein.

Animal protein is generally more easily absorbed, but the difference is minor and considered inconsequential for most people who consume adequate protein through a varied diet. Cooking and other processing can also improve the digestibility of plant protein.

Yes, many successful athletes follow a plant-based diet. With proper meal planning and attention to a variety of protein sources, it is possible to meet the higher protein needs of athletes.