I haven’t written in months so this may seem to be a random topic, but lately I watched the documentary What The Health which led me to critically examine my own dietary choices. Although the film has a myriad of flaws, it did lend one to think about how eating meat and animal-based products, especially in significant quantities, can lead to poor health for oneself and the environment. Following that, I decided to significantly reduce my meat and animal-based products consumption, so much so that I would say that now I follow a diet which is around 90% vegan.
For people who have decided to switch to a plant-based diet, the most common question is: where do you get your protein? Unlike What The Health documentary makes out, it can be difficult to meet all essential amino acid requirements but it is not impossible or even that challenging. The majority associate meat with protein; this leads to the question of what is protein and why do we need to eat it?
Protein makes up most of the dry mass of the cell and they can be thought of as the “workhorses” of cellular function. This means that every living thing will contain protein. Proteins are made up of smaller units called amino acids; there are twenty of them but humans need to get nine of these from their diet – these are the so-called essential amino acids – and the remaining twelve we can manufacture in our own bodies. Amino acids are strung together by peptide bonds – to form the primary amino acid sequence – which then undergoes a folding process to make the final, folded tertiary structure of a protein. Many proteins interact to form larger machines which carry out major cellular function. For example, check out ATP Synthase:
This is an enzyme which makes all of your cellular ATP, the energy currency of the cell, without which you would die. A protein can also interact with itself to from a so-called quaternary structure. In short: proteins are important and it would follow you would need to eat enough of it for your body to function optimally. Now, there is no difference in the amino acids found in plants and those found in animals and the other domains of life, such as fungi, bacteria, and archaea.
If proteins are found in all living beings, and they all are composed of the same building blocks – amino acids – then why is it that meat is considered to be the “best” source? It all has to do with what you are eating. Meat is essentially animal muscle tissue, which allows all animals to move in their environments. It can be seen as a concentrated source of protein (for those interested you can read more about muscle tissue here), with non-collagen sources containing all nine essential amino acids. When you eat plants, however, you are eating different tissues which will affect the ratio of essential amino acids you are getting. For example, tubers such as potatoes contains mostly starch, a store of glucose in plants, which is great for providing a quick energy supply to plants coming out of hibernation, but not so great for providing all essential amino acids that humans need (it should be noted, however, that potatoes are not a poor source of protein either). With plants, variety is the key to getting the essential amino acid requirements; there is a great post by Jack Norris of veganhealth.org explaining what you need to eat on a daily basis to meet your amino acid requirements.
There is nothing magical about the protein found in meat. You can get all of your protein requirements from a plant-based diet, which obviously mutes the question of ethics and has many benefits for health and the environment (meat also contains saturated fat and cholesterol, which is not good when eaten at high-enough quantity). Why not try it?