Miranda has a Master's in Human Nutrition from Christian-Albrechts-Universität and a passion for promoting accurate nutrition information.
When I speak to people about eating more fruits and vegetables and eating less meat, I am infallibly confronted with some variation of, “But what about my protein!”
Quite frankly, that’s probably the exact answer I would have given ten years ago. It’s what we’re taught all the way through our childhoods. What our parents lectured us about when we didn’t want to clear our plates. It is drilled into the foundations of our world view: meat is protein. And the only source of protein. And without protein you can’t build muscle. You will get weak. And sick.
Now, while there is truth buried at the heart of this paradigm, it is such an oversimplified version of the truth, that it pushes up against being a lie. Unfortunately, this near-lie informs many other beliefs and assumptions that, then, do become lies.
I am amazed at how often I hear and read absolutely false and misleading information about protein or muscle. A good chunk of it is linked to ads trying to sell some kind of bar, or powder, or shake. And I get really, really frustrated. These companies are taking advantage of an oversimplified half-truth to take people’s money. And it is to no small extant, my fault - the fault of those in my profession for the last several decades. We have done the public a disservice by allowing such an oversimplified narrative to dictate how we talk about protein for so long. If we spoke about protein in a more detailed and comprehensive way, companies would not be able to make the bogus claims they do, and get away with it.
With that in mind, I wanted to take the time to put together this article addressing the most basic aspects of protein to shore-up my readers against half-truths, deceptions, and scams.
What is protein, really? What does our body do with it when we eat it? And how did we come to believe that meat is the only viable source?
What Is Protein?
Protein is an umbrella term covering millions of unique complexes called proteins. Each protein molecule is made up of an exclusive combination of hundreds, thousands or even millions of tiny molecules called amino acids.
There are 20 amino acids that can be used to build proteins. Each amino acid has its own unique properties. Some are small, some are big. Some attract water, some repel it. Some are bendy. Some are stiff. By combining the unique properties of these amino acids into unique sequences, proteins can be given essentially any character or ability.
One of these abilities is converting energy you eat into the movement of your body – arms, legs, mouth, eyes—all of it. This is the ability of two proteins, called actin and myosin, that are found in extraordinary numbers in your muscle cells. Proteins are responsible for making sure your muscles are healthy and strong!
But other amino acid sequences have totally different abilities. Some proteins detect light and color, allowing you to see. Some can build strong, light ropes that you recognize as hair, which is used to keep you warm. Some act as tiny scissors that chop up food you eat, so you can absorb it. Some have a tiny pocket that can hold onto oxygen molecules, so they can be transported through your body. Some have the ability to stick to DNA, wrapping it up tightly like thread on a spool to keep it untangled and safe from harm.
Essentially, anything you can think of your body, your organs or your cells doing, it is actually done by proteins.
Proteins are the foundation of cellular life.
Every single living cell requires proteins to survive. Every cell, in every organ, in every living thing—from bacteria, to birch trees, to blue wales, to us.
Essentially, anything you can think of your body, your organs or your cells doing, it is actually done by proteins. Proteins are the foundation of cellular life.
How Do Cells Make Proteins?
So how do cells know what sequence of amino acids will give them the right abilities? Their DNA.
Every cell’s DNA contains lists of the specific sequence of amino acids that need to be stuck together in order to make the right proteins to allow the cell to survive. The cell (well, a group of proteins in the cell, actually) reads these instructions, grabs the right amino acids and links them together in the right order.
So where do cells get the amino acids to put together their proteins? Most plants cells have proteins that can make amino acids from other molecules for them. But animals have invented a trick so that we don’t have to make them all ourselves – we steal them from our food. Herbivores steal amino acids from the plants that made them, and carnivores steal them from other animals that stole them from plants.
Since most amino acids aren’t just floating around in the cell, though, we can’t just grab them directly. Rather, we have to steal the proteins that they made with their amino acids. This is what is actually being talked about when people talk about dietary protein – the proteins in the cells that make up our food.
We take these proteins and pull them back apart into individual amino acids. Once we have a pile of amino acids again, we fish out the ones we need and put them together in the right order for our own proteins.
The Meat Fallacy
So, if proteins are found in every single living cell, where did the idea come from that meat is the only valid source of protein.
This idea cropped up at the beginning of nutritional science, just after we learned how proteins are made and how we get amino acids out of our food. Scientists studying proteins in food found out pretty quickly that the sequences of amino acids found in animal proteins are a lot closer to the sequences we make ourselves than those from plants. This makes sense, since we are animals and our DNA instructions are much closer than those in plants!
The scientists simply assumed that this necessarily meant that animal proteins were better for us. See, the idea was, if the sequence of a protein was very close (or even identical) to the one we were trying to make, we could pull it and reassemble it basically instantly. And the more quickly and efficiently the proteins that run our cells could be built, the better it must be for how well our cells work. The better our cells work, the better or organs work. The better our organs work, the healthier we are.
This was considered particularly true for one particular group of organs. Can you guess which ones?
Yep. Our muscles.
Animal protein was assumed to be great for the strength and health of our muscles because we eat the muscles of other animals. Like ours, animal muscles use actin and myosin to move. Eat actin and myosin, make actin and myosin more efficiently. More actin and myosin, healthier muscles!
It wasn’t a bad hypothesis. It’s logical, definitely! But it turns out, it was wrong.
Plant Protein and Human Health
We now know that, even though plant proteins really are “less efficient” than animal proteins at providing us all the amino acids we need to build our own proteins quickly, they are actually better for our health.
Well, partially, it is because of what the proteins come packaged with, which the original theory had fully ignored. Meat comes with viruses, bacteria, cholesterol, hormones and saturated fat, which can all be detrimental to human health. In contrast, plants proteins come with phytonutrients, antioxidants and fiber, all of which provide health benefits.
But primarily, it is because we were fundamentally wrong about efficiency and health. Building new proteins from dietary amino acids slowly is actually healthier!
See, we’ve discovered that making new proteins too quickly taps into ancient biological wiring that tells the body: “Hey! There’s plenty of food! Let’s hurry up, grow and make babies before the food disappears again.” Unfortunately, our bodies, like all animals, trade off the ability to reproduce with the ability to live a long time. So, by offering your body lots of proteins very quickly, it decides to let your cells age more quickly.
Aging cells cannot work as well as younger cells. They can’t perform their jobs as well as they should and they cannot heal as well. Aging cells have been linked to diseases, such as heart disease, diabetes and cancer.
Additionally, if the quick rate of proteins being made triggers your cells “hurry up and grow” far too much, the growth can get out of control, leading to cancer.
Slow, steady, inefficient production of new proteins in your body produces the opposite effects: helps slow cellular aging and does not promote cancer growth.
Why Do We Still Believe That “Protein = Meat”?
If scientists have shown that protein is in all foods, and animal protein is actually worse for human health than plant protein, why is the idea that “protein comes from meat” such pervasive “knowledge”?
It’s hard to say, exactly. Maybe it’s because nutritional scientists haven’t tried hard enough to explain their new findings. Maybe it’s because it undercuts what many of us want to believe about the healthfulness of culturally traditional diets. Maybe it’s just too good of a money maker for companies. Or maybe it’s because, at the end of the day, it’s hard to believe Grandma didn’t know what she was talking about when she said you wouldn’t grow if you didn’t finish your steak.
I know it’s not easy to redefine and recategorize “protein” in your thinking from “meat” to “food” and “muscle” to “whole body.” It was a struggle for me, too. But it really is worth the hassle. It helps empower you to make informed decisions about your diet that can help protect your body from disease and your wallet from scams!
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2017 Miranda Poenicke