Protein, protein everywhere. It’s true, protein is involved virtually every single cell and process in our body. From rebuilding tissue and muscle, hormone production, immune health, enzymes, digestive health, providing a source of energy, and providing cell structure to the growth of our hair, skin, and nails, protein is key.
But what about those following a plant-based diet? Everyone always wants to know how vegetarians are getting their protein, and old-school nutrition theory was that we had to get serious about combining proteins in order to be healthy on a vegan or plant-based diet. We now know that our bodies are smarter than that.
Here’s the deal with combining proteins: a protein that contains all nine essential amino acids is referred to as a complete protein, or sometimes as a high-quality protein. If a protein is very low in one or more essential amino acid, it’s referred to as an incomplete protein. Most (but not all) plant-based proteins are incomplete. To form a complete protein, it’s necessary to combine foods that can make up the missing essential amino acids. These are called complementary proteins.
When we consume protein, it gets broken down into individual amino acids in the gastro-intestinal tract and stored in an amino acid ‘pool’. Amino acids are later taken from the pool and put back together as new proteins. The entire amino acid pool gets exchanged three to four times per day. So long as there’s a constant supply of amino acids entering the pool (some from the diet, some from protein biosynthesis), we’re all good.
Our daily protein requirements are calculated based on body weight. The standard formula is 0.8g protein per kg body weight. For example, if a person weighed 150lbs / 2.2 = 68kg x 0.8 = 54.5g protein per day.
If you’re eating a strict vegan diet the recommendation is to bump up to 0.9g per kg body weight since some plant-based proteins aren’t used by the body as efficiently as animal-based proteins are. That means the same 150lb person would require 61g protein per day on a strictly vegan diet.
There are plenty of great (and delicious!) sources of plant-based protein. For example:
- 100g tempeh: 18 grams
- 1 cup cooked lentils: 18 grams
- ½ cup shelled edamame: 13 grams
- 1 cup canned black beans: 15 grams
- 1 cup canned kidney beans: 13 grams
- 100g firm tofu: 12 grams
- 1 cup canned chickpeas: 12 grams
- 3 tablespoons hemp seeds: 10 grams
- 2 tablespoons peanut butter: 8 grams
- 1 cup plain soymilk: 8 grams
- 1 cup cooked quinoa: 8 grams
- 2 tablespoons nutritional yeast: 8 grams
- 30g (about ¼ cup) dry roasted peanuts: 7 grams
- 30g (about ¼ cup) almonds: 6 grams
- ½ cup rolled oats: 5 grams
- 1 cup broccoli florets: 3 grams
- 1 cup steamed kale: 3 grams
Hi Dave. Sorry for the delay in response. I for some reason have not been getting comment notifications on these posts, so it was only today when one of the editors alerted me to your comments that I was made aware of them.
The idea that combining proteins is outdated is addressed in the second paragraph of this post. Specifically: “old-school nutrition theory was that we had to get serious about combining proteins in order to be healthy on a vegan or plant-based diet. We now know that our bodies are smarter than that.”
And while it’s true that plant foods contain all nine essential amino acids, with the exception of soy, they are always very low in one or two, often containing only trace amounts, which is why they are classified as incomplete proteins. For example, you could meet your daily protein needs by eating nothing but brown rice, but it would take more than 14 cups of brown rice each day to meet your needs for lysine. But, add some beans or lentils to a serving of brown rice, and not only would you meet your total protein needs much more easily, but you’d satisfy your daily lysine requirements as well. So while you *could* meet your daily protein needs on nothing but grains, or nothing but lettuce, you’d always fall short on certain amino acids.
And while it’s not common to see western vegans with obvious protein deficiency (we don’t typically see western vegans get kwashiorkor protein energy malnutrition – although it’s not unheard of) it doesn’t mean that all vegans and vegetarians consume optimal amounts. As a vegetarian of over 25 years myself, and as a practicing nutritionist, I’ve seen the toll that suboptimal protein status can take on people. Vegans who don’t eat enough calories or don’t eat any or enough legumes definitely run the risk of getting too little protein in their diets. Careful protein combining has turned out to be unnecessary – as I stated in this article – but being mindful of where to get protein and that plant-based proteins are typically deficient in their amino acid profiles is a key to being well nourished for many people.
Thanks for reading.
How disappointing. Another “expert” peddling the same silly fear mongering about plant-based diets.
Thank you so much for sharing, this is very useful.