Hey vegetarians, are you getting enough COMPLETE protein in your diet?

Last week, I was giving my husband a slice of toast with peanut butter on it which had a total of 6.5 grams of protein.  Definitely a good amount of protein for a small snack like this.  

My special rule of thumb is, if a small meal or snack had 3 grams of protein or higher in the food, it’s considered a high protein option. 

I was telling my husband, “You’re getting a good amount of protein in this peanut butter toast!” 

He replied, “It’s a different type of protein”.

This really had me thinking- wait, but is it? 

I had to dig back into my brain during those long days of undergrad nutrition where we talked about protein and amino acids to find the answer so let’s take a little stroll down memory lane together. 


Amino acids are the building blocks of protein.  We need protein for different functions in the body such as preservation of lean body muscle mass, immune function and supporting bone structure.

There are 20 amino acids that our bodies need to function adequately.  These amino acids are characterized as essential and nonessential. 

Essential amino acids are needed from the diet, they are “essential” to the body.  There are 9 essential amino acids. 

Nonessential amino acids can be made in the body and therefore, are not needed in the diet.   There are 11 nonessential amino acids. 

The best sources of essential amino acids are animal sources such as eggs, dairy, poultry, meat, and seafood.  They are the best sources because they have ALL 9 essential amino acids present in them which makes them a complete protein. 

Plant-based protein sources such as whole-grain bread, beans, or peanut butter are usually lacking one or more essential amino acids in them which makes them incomplete proteins. 

Remember, we want complete proteins in the diet because our body requires all 9 essential amino acids for individual functions such as energy production, precursors to neurotransmitters and tissue growth.  These essential amino acids function individually and are ALSO serve as the building blocks to protein as mentioned at the beginning of this article.  A protein needs all of its amino acid building blocks to function properly.

I remember talking about this topic with my family years ago when I was first learning about vegetarian diets.  A lot of Indian food is vegetarian and I was wondering, well how are vegetarians meeting their protein needs in the diet? 

My aunt was telling me, well that’s why many Indian meals include “complementary proteins” to make up missing essential amino acids in their diet.

A new term here, complementary proteins.  What the heck is that? 

Complementary proteins are proteins from vegetarian food sources that are missing one or more essential amino acids that when combined make a complete protein.

For example, most beans & lentils are low in the essential amino acid methionine and high in the essential amino acid lysine.  Both brown & white rice is low in lysine but high in methionine.  Put em’ together, you got yourself a COMPLETE protein!

Other complementary proteins include hummus & pita, peanut butter on whole-wheat bread, steel-cut oatmeal with peanut butter or pumpkin seed and spinach salad with nuts & seeds.   

There are a few vegetarian food sources that are complete proteins on their own and these include soy, quinoa, and buckwheat.

Eggs, yogurt, cheese & milk are also great animal sources of complete protein.

So now the question is, should vegetarians be monitoring their essential amino acid intake to make sure they’re getting adequate intakes of each?

And thank goodness, the answer is no.

If you’re a vegetarian or following a plant-based diet, you can ensure the intake of all essential amino acids daily as long as you eat a variety of plant protein daily. 

Consuming a variety of incomplete plant-based protein sources such as nuts, seeds, vegetables, whole grains, beans & lentils will allow your body to make up for missing amino acids in each individual food.  Also note, this does not have to be done over the course of one meal but rather during the course of an entire day.

No matter if your vegetarian or non-vegetarian, everyone can receive adequate amounts of complete protein in the diet. 

Photo: https://unsplash.com/@annapelzer

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