Blog post

Vegetarians You Can Stop Worrying About Complete Proteins

March 8, 2015

Meat eaters used to criticize the vegetarian diet as not having enough protein.  Well, most people have finally woken up to the fact that it is actually easy to get enough protein from plants.  So, now those meat advocates are switching their argument.  They say that “vegetables aren’t complete proteins, so vegetarians can end up with amino acid deficiencies.”  This has caused some to say vegetarians need to follow complex protein-combining systems to ensure adequate amino acid intake. Vegetarians, you can relax.  There is no need to worry about protein combining!

What Are Amino Acids?

Let’s step back a minute.  A protein is a molecule which is made up of amino acids.  There are 20 different amino acids which are used by humans.  Of these, 9 are considered “essential” because our bodies cannot make them on their own.  The remaining are called “non-essential” amino acids because our bodies make them out of essential amino acids.  The term “non-essential” is a bit confusing though in that we really do need them for functioning.  We just don’t have to get them from dietary sources.

What is a Complete Protein?

A complete protein is a food which contains enough of all 9 essential amino acids for your body to function.  A food could have all 9 amino acids and still not be considered “complete” if it didn’t have high levels of all of 9 amino acids.  An example of this is corn, which has all 9 amino acids, but not enough lysine per serving to hold your body over.  Most protein-rich foods do contain all the amino acids.  They just don’t contain enough of them to be considered complete!

Most Vegetarian Foods Are Not Complete Proteins…

It is true that most vegetarian foods are NOT complete proteins.  Of course, there are exceptions to this, including vegan complete proteins like quinoa, soy, hemp, and chia seeds. But, even if you aren’t eating these vegan complete proteins, you probably still don’t have to worry about combining proteins in order to get all your essential amino acids.

If you were to try to subsist on corn alone, you could easily meet your protein RDAs.  A typical adult needs just 46-56 grams of protein per day and 4 cups of corn (at 16 grams of protein per cup) would put you well over the RDA.  But, corn is an incomplete protein because it lacks lysine.  So, you could end up with a lysine deficiency.

Actually, if you ate A LOT of corn, you wouldn’t end up with a lysine deficiency.  That is because corn does contain some lysine, but not enough per serving to meet RDAs.  A typical adult would have to eat about 10-12 cups of corn to get enough lysine.

Luckily, most of us don’t try to subsist on corn alone.  Most of us eat a varied diet which includes many types of proteins.  You are probably even getting some protein from places you don’t expect it, like the 3 grams of protein you got from snacking on raisins.

There is no evidence which shows you need to get all of your amino acids at the same time.  So, if for some reason you only ate corn for lunch, you would be lacking lysine for that meal.  But, chances are you will season your dinner with dried parsley (super rich in lysine) and adequately compensate for what you missed during lunch.

The bottom line?

Ignore all the alarmist advice telling you that vegetarians need to come up with complex protein-combining strategies.  So long as you are getting your protein from a variety of sources, you are probably getting all of your essential amino acids.

image credit:
Confused by collegedegrees360
Attribution-NonCommercial-ShareAlike License


To receive exclusive Beyond Meat® offers, updates and more.