I remember when I was about 11 or so, I wanted to be a vegetarian. I wasn’t sure why then, but I wanted to be. My mother somewhat caved into my desires and told me that I needed to learn about combining protein – something she had read about.
The idea was that animal protein was a complete protein – it contains all of the essential amino acids needed for your body – and plant protein was an incomplete protein – it only contains a subset of the essential amino acids. It was said that in order get the protein you need from eating plants, one must combine plants in meal so that all of the amino acids are covered. If the proteins were not combined, you would not get the protein that you need.
So I went through my entire adolescence believing this. I wasn’t a vegetarian for all of it, but I did eat a lot of vegetarian dishes.
At university and as an adult, as I learned more about nutrition on my own, I realized that I never heard anything about protein combining. I just sort of forgot about it as the years went on, but now I am curious…what happened to the idea of protein combining?
Turns out the idea of protein combining was completely made up!
The idea was first promoted in a book called Diet for a Small Planet, in 1971. The idea was picked up by the the National Research Council and the American Dietetic Association, and they advised vegetarians to combine their proteins. Let’s say this again…major organizations picked up an idea from a book that was not based in science.
The author is not an idiot, but she is certainly not a scientist. This is obvious from her statement in 1981 (ten years after the book was written):
“In 1971 I stressed protein complementarity because I assumed that the only way to get enough protein … was to create a protein as usable by the body as animal protein. In combating the myth that meat is the only way to get high-quality protein, I reinforced another myth. I gave the impression that in order to get enough protein without meat, considerable care was needed in choosing foods. Actually, it is much easier than I thought.”
And she is right. It is very easy to get enough protein simply by eating a variety of plants, grains and legumes. There is no special planning needed. The human body has evolved to extract what it needs from a variety of different foods obtained through a variety of different diets.
While it is true that plants are not a complete protein, the body does a fine job of synthesizing complete protein for building body tissues from various plant proteins.
Image Credit: Creative Commons photo by arimoore