Quality protein doesn’t always have to mean chicken, turkey or fish. Ecological, ethical, health concerns…There are plenty of reasons to replace meat with a plant-based diet. But even though meat-free diet can be healthy and can have a lot of benefits of its own, plant complete protein sources containing all essential amino acids are a little bit harder to find.


There 22 amino acids, which are also called “building blocks” of protein. 9 of these 22 amino acids are considered essential. It means that unlike the rest of them (still important as a food source) they can’t be made by our bodies and can be obtained only throughout the diet. Unlike eggs and meat, most plants will miss on some of these essential amino acids or contain too little of it decreasing at the same time its bioavailability. Therefore plants often have to be combined to obtain plant complete protein.


Today, more traditional biological methods that used to set standards in reflecting true protein quality are replaced by Protein Digestibility-Corrected Amino Acid Score (PDCAAS). Same as traditional bioavailability scores, PDCAAS will also be much lower in plants than in meat-based diet, even if these are plant complete protein sources. But this is simply a compromise for someone who is on a purely plant-based diet.

Despite the fact PDCAAS is considered more accurate, bioavailability and digestion of the amino acids and minerals in certain foods is not yet fully understood and its true value is still experimental. We know that bioavailability can vary and may be compromised due to such factors as:

# Plants/foods may miss organic compounds which allow the body to easily break protein down.

# Production and extraction methods can render the bioavailability of the same product higher or lower.

# Certain types of fibre can inhibit protein absorption and reduce it by as much as 10%

# Anti-nutrients like phytic acid, tannins, or protease inhibitors are often found in legumes and grains and also interfere with absorption of protein and other compounds. However, these can be well counteracted at the final step of preparation by using certain cooking practices (eg. soaking, sprouting).

A PDCAAS value of 1 is the highest, and 0 the lowest.



No, humans generally don’t need every essential amino acid in every single bite of food in every meal they eat. If you eat oat flakes in the morning, legumes at lunch, and some salad in the evening, your body will pool together all the essential amino acids from these plant-based food sources and use them as needed to make proteins.

However, this “pool” of amino acids may not be sufficient to support the nutritional requirements and performance goals of professional athletes and avid fitness enthusiasts. Strength athletes, in particular, will require higher protein intake with meals which are balanced and well equipped with all essential amino acids in order to make optimal progress.

That’s why if you fall into this category and are on plant-based diet only, combining plant proteins might be necessary. Having a single plant with all 9 essential pieces of protein on your plate is a bonus here and can make your life much simpler. Here are 5 best plant complete protein sources.



Unlike other grains(technically a seed) that often miss the amino acid lysine or contain very little of it, quinoa contains lysine along with the other eight essential amino acids in amounts that are not only well balanced for the needs of humans, but also place its protein bioavailability at the top of plant food sources. It’s also low in gluten and is full of fibre, iron, magnesium, manganese and other micronutrients. Quinoa also contains carbohydrates making your meal even more diverse.

1 Cup (185 grams,cooked)

Protein: 8 grams
Carbohydrate: 39.4 grams
Fat: 3.5 grams
Kcal: 222

Bioavailability: 84
PDCAAS: – 0.60


 Best Plant Complete Protein Sources- Hemp

Yes, marijuana comes from the same plant, but I have to disappoint you… you won’t get you high 🙂 Hemp seeds contain only a trace amount the THC active ingredient. Hemp contains 20 amino acids, including the nine essential amino acids that your body is unable to produce on its own. But, even though it is classified as a complete protein source, it is low in lysine and leucine, and therefore needs supplementation with other plants (eg.pumpkin seeds, almonds, oats). Hemp also has been shown to have positive effects on the immune system and fatigue, and it packs a bunch of other dietary ingredients like fibre, minerals, chlorophyll, and antioxidants.

4 Table Spoons – about 30g

Protein: 12 grams
Carbohydrate: 11 grams
Fat: 3 grams
Kcal: 120

Bioavailability: 87
PDCAAS: – (dehulled) 0.66


 Spirulina - Best Plant Complete Protein Sources For Athletes

This blue-green alga is named after its spiral shape and is mostly protein by dry weight (about 70%). From a qualitative point of view, spirulina has a full protein profile and contains all the 9 essential amino acids forming 47% of total protein weight. The sulphur-containing amino acids cysteine and methionine are present in less optimal amounts, but still, they are more than 80% of the ideal level defined by the Food and Agricultural Organisation (FAO).

The protein content can vary by 10-15%, depending on the time of harvesting in relation to daylight. Also, it appears that some industrial drying methods can reduce methionine content by as much as 30%. Perhaps, for these reasons, some sources misleadingly quote spirulina as having a non-complete amino acid profile. Some authors also under-represent Lysine while others consider the level adequate.

In spite of that the biological value of spirulina is astounding, its bioavailability slightly decreases because it doesn’t have cellulose (cellulose allows your body to easily break down proteins) in its cell walls. Supplementation with a good source of sulphur-containing amino acids and lysine and/or histidine will do an excellent job here.

One Serving of Dried Spirulina – about 355 grams

Protein: 12 grams
Carbohydrate: 5 grams
Fat: 1.5 grams
Kcal: 60

Bioavailability: 75-80


 Chia Seed - Best Plant Complete Protein Sources For Athletes

Chia seeds contain 18 of the 22 amino acids, but most importantly it includes all nine essential amino acids that can not be made up by our bodies. Again, the essential amino acids like threonine, lysine and leucine can be present in less than optimal amounts and can vary in content due to the individual characteristics of each crop, weather conditions during the growing season, or the nutrients in the soil. Pairing chia seeds with spirulina powder or lima beans will ensure an optimal amino acid profile.

They are also a great source of omega-3 fatty acids, and they contain more fibre than nuts or flax seeds. Chia is also full of calcium, iron, zinc, and antioxidants. But perhaps the best thing about chia is that it forms a goopy gel when combined with water or milk. This makes them great for making smoothies thicker or making healthy puddings and replacing eggs in vegan baking. You can also simply sprinkle it on your food.

6 Table Spoons – about 84 grams

Protein: 12 grams
Carbohydrate: 42 grams
Fat: 3 grams
Kcal: 411

PDCAAS: 0.48 – 0.80(chia flower)

Although it looks like a lot of calories for such a small amount of food, high amounts of fibre that chia contains will ensure that most of this calories are not going to stick around.


Plants with all essential amino acids - buckwheat

Despite its name, it’s one of the favourites amongst gluten-free plant eaters since it doesn’t contain any wheat or the protein gluten. In addition to containing all essential amino acids, a unique amino acid composition gives it special biological activities including cholesterol-lowering and anti-hypertension effects. Buckwheat can also improve digestion by relieving constipation. It also provides a bunch of antioxidants, vitamins, minerals, it has no fat and relatively few calories.

2 Cups of Cooked Buckwheat

Protein: 12 grams
Carbohydrate: 66 grams
Fat: 2 grams
Kcal: 310

Bioavailability: 80
PDCAAS: 0.56

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