Protein in brief
The question "where do you get your protein?" is all too familiar for many of us following a plant-based lifestyle. While the power of plant-based foods is on the rise, protein is often still equated with animal-based foods such as meat, fish, eggs, and dairy. Not only is it possible to get enough protein on a plant-based diet though, it's also relatively easy when enjoying a variety of foods!
Functions of protein
Protein is one of three macronutrients, alongside carbohydrates and fats. It's a source of energy that has important structural and functional responsibilities in the body. Here are a few of proteins roles:
- Structure: proteins such as collagen and keratin play a structural role in muscles and other tissues.
- Hormones: proteins can act as chemical messengers to transmit signals, such as insulin.
- Transportation: proteins help with transportation throughout the body. For example, hemoglobin is a protein that carries oxygen from the lungs to body tissues.
- Immune defence: antibodies and immunoglobulins are proteins that protect the immune system.
- Enzymes: proteins help speed up chemical reactions in the body and partake in several metabolic processes.
The building blocks of protein
Protein is a large structure made up of smaller building blocks called amino acids. There are twenty amino acids that the body needs, eleven of which are "non-essential" and nine which are "essential".
- "Non-essential" amino acids mean that our bodies can make them on their own. Due to this, seeking food sources rich in these amino acids isn't necessary.
- "Essential" amino acids mean that our bodies cannot make them, so we need to consume them from food sources. The nine essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
When it comes to protein needs, we can consider both the quantity and quality of protein. Let's focus on the quantity side first.
Quantity of protein
How much protein we need depends on several factors including our age, body composition, activity level, health status, presence of any illnesses, and so on. It's true that plant-based proteins may not be as efficiently absorbed in the body, but the difference is quite small.
The protein requirements for an average adult is 0.8g/kg - 1.0g/kg of body weight. For example, if someone weighs 143lbs (143 lbs / 2.2 kg = 65 kg), then their minimum estimated protein needs would be 52-65g per day (0.8 g x 65 kg and 1.0 g x 65 kg).
A note on athletes
Another common misconception is that all people who exercise require a high protein intake. It's true that athletes who train at an elite level have higher requirements at about 1.2g-2.0g/kg of body weight. For the average adult who exercises recreationally though, such as 30 minutes several times a week, 0.8 g - 1.0 g protein per kg of body weight is enough to meet needs.
Overall, the general population that enjoys exercise is able to get enough protein from balanced meals and snacks without needing to drastically increase protein intake. To learn about creating a nutritionally balanced plate that includes protein, see our plate method article.
Other populations to consider
Protein requirements are also higher for young children, elderly populations, and pregnant individuals. Note that it's always best to speak with a healthcare professional, such as a dietitian for personalized nutrition requirements.
Protein is found in a wide variety of legumes, grains, vegetables, nuts, and seeds. There are loads of plant-based food sources, below is a list of just a few top sources with approximate grams of protein per serving.
- Tempeh (½ cup) - 17 g protein
- Tofu (½ cup) - 13 g
- Edamame (½ cup) - 9 g
- Beans (most varieties) (½ cup) - 8 g
- Rolled oats, uncooked (½ cup) - 5 g protein
- Quinoa, cooked (½ cup) - 4 g
Nuts and seeds
- Hemp seeds (¼ cup) - 13 g protein
- Pumpkin seeds (¼ cup) - 11 g
- Peanuts (¼ cup) - 9 g
- Chia seeds (¼ cup) - 8 g
- Peanut butter (2 tbsp) - 8 g
- Almond butter (2 tbsp) - 7 g
- Tahini (2 tbsp) - 5 g
- Green peas, cooked (1 cup) - 8 g protein
- Artichoke, cooked (1 cup) - 5 g
- Spinach, cooked (1 cup) - 5 g
Plant-based milk products
- Soy yogurt (¾ cup) - 6 g protein
- Soy milk (1 cup) - 6 g
Pro tip: soy milk is often recommended because it provides protein similar to cow's milk, whereas other plant-based kinds of milk don't offer this much protein. We can opt to use soy milk where possible to boost our protein intake!
As mentioned earlier, there are nine essential amino acids that we need to get from foods. This is where the quality of protein comes into play. If a food item contains all nine amino acids in sufficient amounts, it's called a "complete protein". Soy is the main plant-based source of complete protein. Other plant-based protein sources are lower in a few essential amino acids, namely lysine and methionine.
For example, most grains tend to be high in methionine but low in lysine, while most legumes tend to be high in lysine but low in methionine. This is where the idea of protein combining emerged. It was thought that if a person combined these "complementary" proteins in the same meal, they would optimize the availability of amino acids as one food group would "make up" for the lack of particular amino acids in the other food group. We now know that we don't necessarily need to consume these complementary foods in the same meal. Simply having them within the same day has the same effect. By consistently consuming a varied diet from all food groups, we'll likely have our bases covered.
In any case, we may find that many commonly eaten foods are already complementary, for example:
- Toast with nut butter
- Hummus with pita bread or whole-grain crackers
- Rice and beans, in a nourish bowl, wrap, or taco
- Stir fry with tofu or edamame served over rice or with noodles
Supplementation & protein powders
Here at PUL, we aim to promote food first where possible. The same goes for protein. It's absolutely possible to obtain adequate levels from food alone, even as an athlete.
If our requirements have been determined to be very high or we're unable to meet our needs from food alone, we may choose to supplement with a powder. Some plant-based sources include soy protein, pea protein, hemp protein, flax protein, chia protein, and brown rice protein. When looking to purchase protein powders, we can try to aim for brands that aren't heavily sweetened and have been assessed for contaminants.
In Canada, for example, once a department of the government has assessed a product and decided it's safe and of high quality, it issues a product licence along with an eight-digit Natural Product Number (NPN), which must appear on the label. Before choosing to buy a supplement in Canada, we could check to make sure it had an NPN number. It may be worthwhile to see if our local government has similar regulations, and if a brand meets those regulations, it may be one to consider.
- Obtaining adequate levels of protein is achievable when consuming a varied plant-based diet. Supplementation isn't necessary, as having a variety of different plant proteins and adequate overall energy intake is usually enough.
- The average adult who exercises recreationally needs at least 0.8 g - 1.0 g of protein per kg body weight. Requirements can vary for different populations, especially differ for children, the elderly, pregnant individuals, and higher intensity athletes.
- Elite endurance and strength athletes require higher levels of protein, at about 1.2 g - 2.0 g per kg of body weight. It's still possible at these ranges to obtain sufficient protein from food sources first, before supplements.
- The best plant-based sources of protein include legumes and grain products such as tofu, tempeh, edamame beans, lentils, peas, beans, quinoa, and buckwheat. Other great sources include nuts, seeds, soy milk, and soy yogurt. Aim to choose whole plant foods over processed vegan substitutes if possible, as these may contain higher levels of sodium and saturated fat.
- Focus on obtaining protein from food first, before turning to supplements.