Understanding What Two Vegetables Make Complete Proteins in a Balanced Diet

October 21, 2025 •

3 min read

While protein combining at every meal was once considered crucial for plant-based eaters, this idea has largely been debunked, as the liver stores essential amino acids for later use. This article explores the science behind what two vegetables make complete proteins when combined and reveals that a varied diet is the true key to getting all essential amino acids.

Quick Summary

This article explains how combining complementary plant foods like legumes and grains, such as peas and rice, creates a complete amino acid profile. A diverse diet ensures you get all essential amino acids throughout the day, eliminating the need to combine them at every meal.

Key Points

Combine Legumes and Grains: Pairing a legume like peas with a grain like rice is the classic method for creating a complete protein from plant-based foods.
Variety is Key: You do not need to combine complementary proteins in the same meal, as the body maintains a pool of amino acids throughout the day.
Soy is a Complete Plant Protein: Foods derived from soybeans, such as edamame, tofu, and tempeh, are naturally complete proteins and excellent additions to a plant-based diet.
Quinoa and Seeds are Complete Too: Grains like quinoa and seeds like hemp and chia are among the few complete plant-based proteins that don't need combining.
Mix and Match for Flavor and Nutrition: Diversifying your protein sources with different combinations ensures you get a wide array of vitamins, minerals, and amino acids for overall health.
Potatoes are a Complete Protein: While not often thought of for protein, potatoes are a complete protein source containing all nine essential amino acids.

The Science of Complete Proteins

Proteins are composed of amino acids, nine of which are essential and must be obtained through our diet because the body cannot produce them. A complete protein source contains all nine essential amino acids in sufficient amounts. Animal products are typically complete proteins, while most individual plant foods are considered incomplete, meaning they lack one or more essential amino acids. However, this doesn't mean a plant-based diet can't provide complete protein.

Combining Vegetables for Complete Proteins

To form complete proteins from plants, combining complementary sources is a common strategy, usually pairing a legume with a grain. While individual plant foods may be incomplete, they offer different amino acid profiles. When combined, they provide all essential amino acids. It is not necessary to eat these combinations in the same meal, as the body maintains a pool of amino acids throughout the day.

The Perfect Pair: Peas and Rice

Peas and rice exemplify a complementary pairing. Pea protein is rich in lysine but low in methionine, while rice protein is high in methionine but low in lysine. Combining peas and rice, whether in whole food meals or blended protein powders, creates a complete protein profile.

Other Complementary Vegetable Combinations

Beyond peas and rice, various other plant combinations create complete proteins, a practice found in traditional cuisines globally. Examples include:

Beans and rice
Hummus and pita
Pasta and peas
Lentil soup with whole wheat bread

Don't Stress: The "Protein Combining" Myth

Contrary to a past belief, it's not essential to combine specific plant proteins at every meal. The body can use an existing pool of amino acids throughout the day. A varied diet incorporating a mix of grains, legumes, nuts, and seeds is sufficient to ensure complete protein intake over a 24-hour period. This approach simplifies plant-based eating, emphasizing overall dietary diversity.

Naturally Complete Plant-Based Proteins

Some plant foods naturally contain all nine essential amino acids, making them complete proteins on their own. Including these foods enhances protein intake without needing combinations. Examples include soy products (tofu, tempeh, edamame), quinoa, hemp seeds, chia seeds, buckwheat, pistachios, and potatoes.

Comparison of Complementary Proteins


Feature	Pea Protein	Rice Protein
Amino Acid Profile	High in lysine, lower in methionine.	High in methionine, lower in lysine.
Best For	Muscle growth, appetite control, and recovery due to high BCAA content.	Digestive health, hypoallergenic properties, and a smooth texture.
Weakness	Low in methionine, requiring a complementary source.	Low in lysine, requiring a complementary source.
Combines Well With	Rice protein to create a complete protein blend.	Pea protein for a balanced amino acid profile.

Creating a Balanced Plant-Based Meal Plan

Ensuring complete protein intake on a plant-based diet relies on variety. Meal ideas can include combining complementary proteins like beans and rice or incorporating naturally complete sources like tofu or quinoa. Snacking on options like hummus and whole wheat pita or nuts and fruit can also contribute. A diverse range of plant-based foods helps meet protein needs and offers numerous health benefits. More resources on plant-based protein options are available from the {Link: American Heart Association https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/plant-based-protein-infographic}.

Conclusion

Combining legumes and grains, such as peas and rice, is a classic way to create a complete protein from plant sources. However, the most effective approach to getting all essential amino acids on a plant-based diet is to eat a diverse range of plant foods throughout the day. This ensures a balanced, nutrient-rich diet.

Frequently Asked Questions

No, you do not need to combine complementary proteins at every meal. The body can maintain a pool of amino acids, so as long as you eat a varied diet of different protein sources throughout the day, you will get all the essential amino acids you need.

Yes, edamame (immature soybeans) is a complete protein source. As a soy product, it contains all nine essential amino acids in sufficient amounts.

Yes, it is entirely possible for vegans to get enough protein from food alone. By consuming a varied diet of legumes, whole grains, nuts, seeds, and soy products, they can easily meet their protein needs.

Yes, potatoes are considered a complete protein. They contain all nine essential amino acids, although their overall protein content is lower than many other sources.

Most grains, including rice, are too low in the essential amino acid lysine to be considered complete proteins on their own.

The best way is to focus on eating a wide variety of plant-based protein sources, such as legumes, grains, nuts, and seeds, throughout the day. This ensures you consume all essential amino acids over a 24-hour period.

Yes, pea and rice protein powders are often blended together to create a complete protein source. Since pea protein is low in methionine and rice protein is low in lysine, combining them fills in each other's deficiencies.