Lots of people ask me how I can get enough protein without eating animals. It’s actually very simple, and lots has been written about it already. Here’s a great blog post on plant protein. The author did some math that shows the concept quite well. Let’s start with consuming the recommended half a gram of protein per kilogram of lean body mass- the average for a grown man is 56 grams per day. If you eat a plant-based diet with 14% protein, in a 2000 calorie per day diet, that’s 280 calories of protein. Divide 280 by 4 (because there are 4 calories per gram of protein), and you get 70 grams of protein. That’s more than enough for an adult man, and it’s enough for a pregnant woman who needs more.
What is protein? Proteins are made up of amino acids, which is a fancy name given to a group of molecules held together by covalent bonds (bringing back the high school chemistry!) that all share a common backbone of nitrogen, carbon, oxygen, and hydrogen atoms. Different amino acids configured together make different proteins. Your body needs protein in order for your cells to function and to rebuild itself. Your body creates its own proteins all the time from amino acids it can make on its own. It also gets protein/amino acids from the food you eat. Some amino acids are called essential because these are the amino acids your body cannot create on its own. Out of the 22 amino acids, 9 are essential.
All food has protein; it is a myth that animal protein is somehow the best and you won’t get all your essential amino acids if you don’t eat animals. There’s a lot of food propaganda that equates animals to protein, and somehow leaves plants out of the mix. I’ve read on the internet that animal protein is the only complete protein. This is based on the fact that in one meal with animal protein you can get your essential amino acids. However, your body is smart enough to figure out how to get all the essential amino acids from plants, and you don’t need to eat all of the essential amino acids at every meal.
How much protein do you need, and how much is too much? Adult men need 50-70 grams of protein per day (average 56 grams/day), and adult women need 30-50 (average 46 grams/day) or 70 grams/day if they are pregnant. The average Western meat and dairy diet can give you much more. This can lead to weight gain (which can in turn lead to metabolic disturbances, including diabetes and heart disease), kidney strain and possibly later kidney disease, and dehydration.
If you do need extra protein – say you are an avid athlete who’s building muscles all the time, or pregnant and building another human – there are plenty of plant-based sources that give you more than most plants. Spinach, kale, tofu, hemp, chia seeds, beans, and legumes are all great sources. As always, talk to a dietitian or physician if you’re concerned. I’ve been eating a plant-based diet for the past two years, and I’ve never felt better! I have no more sluggishness, nor do I get that heavy pit feeling in my stomach after a meal that makes me have to lie down and recover. I have tons of energy and am more physically active, stronger, and leaner than I have been in my life.
My take home message is this: if you eat a plant-based diet, you will eat enough protein; and if you eat a variety of foods, you will get all of your essential amino acids.