Complete Plant-Based Protein + Complementary Protein Explained

Not all proteins are physiologically equal. Some proteins are complete proteins, ie proteins that contain all nine essential amino acids. Other proteins are incomplete proteins, i.e. they lack one or more of the nine essentials. 

First, what are these essential amino acids? Well, there are 20 amino acids that combine in different chains to make up protein. Nine of them are called ESSENTIAL because our bodies can’t produce them, so we must get them from food. The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. 

Animal-based proteins are considered complete because they contain all the necessary amino acids (and more!). However, many plant-based sources of protein are incomplete. In order to get a complete plant-based protein it often comes down to combining foods; we call these COMPLEMENTARY PROTEINS. 

Related: Mindful Eating: Finding a Healthy Relationship with Food

Beans and Rice Complementary Proteins
Legumes + Rice are a classic combination.

Let’s Start with the COMPLETE Plant Proteins. 


I rarely recommend consuming soy products as a staple in your diet. This is largely due to processed soy products ubiquitous in our food supply. For more about soy, check out this post by Alissa Vitti

If you DO choose to consume soy protein, Tempeh is made of fermented soybeans and is actually a complete protein. Although we typically lose the probiotic benefit of this fermentation due to pasteurization and cooking, it is still a better-for-you option. Tempeh is rich in protein, calcium, iron, manganese, phosphorous, and magnesium. 


Lentils tend to be very well-tolerated, even on the most restricted diets. They are quite versatile, easy to prepare, and inexpensive. They are 25% protein by weight! Bonus points here as lentils are also an excellent source of fiber

For anyone on an exclusively plant-based diet, lentils are a great alternative to meat that still provides a complete amino acid profile. Try them in a Lentil Bolognese

<<Click Here to get my 15-Ingredient Plant Based Meal Plan>>


Chia seeds are a complete protein; but they also shine in other areas. A 1-ounce serving of chia seeds has 10.6 grams of fiber (both soluble and insoluble). Chia seeds are also a plant-based source of Omega-3 fatty acids (in the form of ALA). AND they contain phosphorous, magnesium, and calcium. Win-win-win. 

While you’d be hard pressed to eat enough chia seeds to significantly contribute to your protein goals for the day, they do make a great addition to smoothies, salads, and bowl meals. 

Related: Oat Milk Chia Pudding

Closeup Chia Oat Blend _ Complete Plant Protein Chia Seeds Vegan
Chia seeds are a complete vegan protein source.


This is actually a gluten-free ancient grain with a nutty taste. To balance out a plant-based meal, this complete protein source also provides fiber, calcium, and some B-vitamins. 

Although it is complete, one cup of amaranth only provides about 5.8 grams of protein. Similar to Chia, You’ll need to eat A LOT to get close to your daily protein needs with this grain. 

<<Click here to try Amaranth Porridge by Bob’s Red Mill>>


As I mentioned, certain plant foods need to be eaten in combination in order to get a complete protein. In traditional cuisines, we’ll often find these foods paired together naturally! Here are a few key combinations:


See? Traditional pairing here. Beans have lower levels of methionine (one of the essential amino acids). Conveniently, Rice is quite high in methionine. When consumed together, beans and rice form a complete protein providing all nine essential amino acids. 

Beans are unmatched in their ratio of soluble fiber. They also provide minerals like copper, folate, iron, magnesium, and zinc. Rice can feel a bit like a “filler food” – but for a vegetarian, this combination should be top of mind. 

Food sources of complete protein on a plant-based diet
Beans are one of my favorite vegan protein sources! (Hidden in my Avocado Toast)


This combination shows up often in seeded and sprouted breads. Ezekiel Bread is a popular sprouted grain bread made with whole grains and seeds. In this combination, it actually contains 18 amino acids! Sprouted grain breads tend to be easier to digest AND the vitamins and nutrients are more bioavailable. 


The classic combination I think of here is the Peanut Butter Sandwich. Peanuts, like other legumes, are low in methionine. When paired with whole grains (or even oats), we get all the essential amino acids for a complete protein. 

Side Note I can’t Ignore: Have you seen the Game Changers graphic comparing a peanut butter sandwich to a steak?! We must take into account caloric density of foods versus protein content when attempting to eat a balanced diet. It is possible to get plenty of protein on a plant-based diet; BUT it takes more awareness and planning!

Complementary Proteins on a Vegetarian Vegan Diet
Plant-based eating can be very healthy with knowledge of protein pairings!

Want to incorporate more Complementary Plant Protein in your diet?

You can save even more time (and money) by shopping with Thrive Market! Use the ‘plant-based’ and ‘soy-free’ filters to find lots of great options.

Wanna really make a difference in your health in 2022? Check out THE ELIMINATION DIET GUIDE.

The Elimination Diet is really a chance to get to know yourself better, to develop personal nutrition, and address lingering symptoms. I believe that nutrition is so individualized. MY diet is going to look very different than your diet, and very different from our friends’ diets. They may all be ‘healthy’! To get to that point, you’ve got to put in the ‘hard work’ of being intentional with food choices and ultimately finding more freedom.

You May Also Like:

Mindful Eating: Finding a Healthy Mindset with Food

What Is the Carnivore Diet?

Shop My Faves:

DISCLAIMERS: The statements made on this website are not intended to diagnose, treat, cure, or prevent disease. You assume full responsibility for how you use this information. Always consult with your physician or other health professionals before making any diet or lifestyle changes. This post may contain affiliate links whereby if you purchase these products I receive a small percentage of the sale price. This allows me to keep the blog running and I thank you for allowing me to do that!


Enter your email below to get on the list for monthly updates from Kate (plus exclusive resources + meal plans!

You have been successfully Subscribed! Ops! Something went wrong, please try again.

Still learning? Here’s more