Somewhere down the line in history, people got the idea that meat is the only food which contains any significant amount of protein. Hence why vegetarians are always getting asked the question "where do you get your protein?"-- even though it is actually very easy to get enough protein on a vegetarian or even vegan diet. To put this in perspective, consider that a cup of lentils has about 18g of protein, so it would take less than 3 cups of lentils to get your protein RDA. Even foods like bananas and spinach contain some protein.
But some people have taken the argument further by saying things like, "but plants aren't complete proteins" and imply that, even though plants do contain protein, that this protein is somehow inferior. So let's look at what the real differences between plant and animal proteins are.
What Are Proteins?
A protein is one of the primary building blocks of your body. They are what make up muscle, bone, skin, hair and many other tissues in your body. If we don't count water, then 75% of our bodies by weight are made up of protein.
There are over 10,000 different types of proteins in our bodies.This number is a bit misleading though, because all of those different proteins are made up of the same 22 amino acids (some sources will say it is 20 amino acids). Amino acids are the building blocks of protein, and they link together in different ways. Depending on how the amino acids are linked, a different protein will be formed.
Of the 22 amino acids humans use, 9 of them are considered "essential" and the rest are "non essential." (Note some sources say there are 8 essential amino acids) Just because the rest are non-essential, it doesn't mean we don't need them. It just means that our bodies can produce them on their own from the essential amino acids. Our bodies cannot create essential amino acids, so we need to get these from food sources.
What Happens When We Eat Protein?
When you eat a food with protein in it (and almost all foods contain some amount of protein – even salad!), your body breaks down the protein into its amino acids.These amino acids are then sent through the body.The amino acids are recombined to create new proteins (remember, there are 10,000+ different types of protein in your body!). So, some of the veggie burger you ate turns into muscle proteins, some into hair proteins, some into hormone proteins, and so on.
Is There Really A Difference between Animal and Plant Proteins?
In terms of components, there is no different between animal and plant proteins.They are both made up of amino acids, and they both contain the same 22 amino acids. However, the ratio of these amino acids is different.
It is commonly cited that "plant foods aren't complete proteins," meaning that they don't contain all of the essential amino acids.Well, this isn't exactly true because there are plenty of vegan complete proteins, like pumpkin seeds, chia seeds, and hemp seeds. But it is true that meat is more likely to contain all the essential amino acids.
Does this mean that vegetarians and vegans won't be able to get all of their essential amino acids? Absolutely not.
Most people don't eat the same thing all day long. So, while it may be true that peas are lacking in the essential amino acid methionine, foods like peppers, spinach, shallots, and tomatoes all contain this amino acid. So long as you eat a variety of foods, you are bound to get all of the essential amino acids you need.
*There is no need to get all amino acids during the same meal! So, you don't have to worry about complex protein combinations to get all your amino acids. Just eat a variety of food throughout the day. Besides, who likes to eat nothing but peas all day long?
Calories, Cholesterol, and Saturated Fat
While there really aren't any differences between plant and animal protein in terms of components (just different arrangements and ratios of amino acids), there are differences in what else accompanies the proteins.
Meat is notoriously high in calories, cholesterol, and saturated fat – all of which is accredited to growing health problems like obesity and heart disease (okay, the cholesterol one is now controversial, but excess calories and fat are definitely no bueno).
To put this in perspective, when we compare a gram of protein from lentils with gram of protein from 85% lean beef:
A gram of beef protein contains 14.25 times more fat than a gram of protein from lentils
A gram of beef protein contains 23 times more saturated fat than a gram of protein from lentils.
There may be even more harmful compounds in meat as well. Studies have long shown a link between consumption of red meat and cancer. Recently, scientists think they have found the culprit in red meat which causes cancer. They found a link between cancer and a molecule found in red meat. The molecule, Neu5Gc, is found in high amounts in beef, bison, lamb, and pork. It is not found in fruits and vegetables. The molecule triggers an inflammation response, which can lead to long-term inflammation and tumor growth.
There are also other studies which indicate that consuming high amounts of meat can be dangerous for your health or cause cancer, such as Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) which form when meat is cooked at high temperatures, or the calcium which is released when high amounts of sulfur-containing meat is consumed.
The bottom line? Vegetarians and vegans may need to worry about some nutrients like iron and B12, but protein probably isn't going to be an issue. You can easily get enough protein and essential amino acids on a plant-based diet, and you will probably experience some health benefits too!