Common Plant-Protein Myths Debunked

Protein.

Hands down the most common question I’m asked when I tell people I eat a plant-based diet (and am a Dietitian) is “How do you get enough protein?!”. What’s funny about this is that so many people actually have no idea how much protein they need to eat everyday, or how much they’re consuming themselves! In this article, I’m going to break down some common myths about protein on a plant-based diet, how much protein you should be consuming, and how you can make sure you’re meeting your needs.

Protein Myths

Plant-protein quantity myth

The number one myth I hear about protein on a plant-based diet is that it’s impossible to get enough of it. This couldn’t be further from the truth. In reality, legumes (beans, peas and lentils) are excellent sources of protein, with just one cup of cooked lentils offering 18 grams of protein, half a cup of tofu containing 10 grams of protein, and half a cup of chickpeas offering 7 grams of protein. Below, you’ll find a comprehensive list of plant-protein rich sources.

Plant-protein quality myth

The rumour has long been that meat-based protein is a better-quality protein source than plant-based protein. While it is true that some plant sources of protein are not “complete” with all nine essential amino acids needed for humans, obtaining all nine essential amino acids (meaning our bodies do not produce them in adequate quantities ourselves) is relatively simple when consuming a whole-foods, plant-based diet (1).

The essential amino acids that are present in animal products are all derived from plants, either from the animal consuming plants directly (i.e. cows) or from the animal consuming other animals (i.e. salmon or tuna). Therefore, it doesn’t make sense for us to assume that in order to obtain adequate quality and quantity of protein, we have to eat animals (1). There are plant-protein sources that provide all nine essential amino acids (2). Otherwise, we can consume various types of whole grains, legumes, leafy greens, nuts, seeds and fruit to obtain all essential amino acids in adequate quantities (2).

Complementary protein myth

The protein combining myth first began when it was discovered that some plants are low in an essential amino acids, meaning various plant-based protein sources should be combined at specific meal times in order to get the complete spectrum of amino acids (3). However, this was refuted decades ago (3). We now know that humans are able to store amino acids throughout the day, meaning that as long as we consume a varied diet of whole grains, legumes, nuts and seeds everyday, ensuring that we combine beans and rice or lentils and whole grains at the same meal time is not necessary (1, 3, 4).

Two amino acids that are of the greatest concern to those following a vegan or plant-based diet are lysine and tryptophan. Lysine is found in low quantities in wheat, rice and other grains. The challenge of getting enough lysine can be overcome by including lysine-rich foods such as peas, beans and lentils buckwheat, quinoa, edamame and other soy foods (1). Lysine is especially important for growth in early childhood, which is why impoverished countries who rely on grains and wheat as their sole protein sources may be heavily impacted (1).

The other amino acid that vegans should pay special attention to is tryptophan, which is essential for the maintenance of body tissue (1). Tryptophan is found in abundance in soy foods, seeds, spinach, green peas, nuts, and pseudo-grains such as buckwheat and millet (1). This is why ensuring that we are consuming a varied plant-based diet filled with whole grains, vegetables, legumes, nuts and seeds is important (1).

So how much protein do we need?

Most people need to consume between 0.8-1.0 grams per kilogram of their body weight per day of protein per day (5,6). This means that for an individual who weighs 150 pounds (2.2 pounds = 1 kg; therefore 150/2.2=68.2 kg) should consume 54.5-68.2 grams of protein (68.2 kg/0.8 g/kg= 54.4g) per day.

Young children, older adults, and those who workout and are active typically require more protein. Endurance athletes require 1.3-1.5 g/kg/day, and strength athletes following a plant-based diet should aim for 1.3-1.9 g/kg/day. Older adults should consume 1g/kg/day of protein (7-10). If considering a vegan or plant-based diet for young children, please consult a Registered Dietitian.

Where do I get protein? (1)

Protein sources (in gram amounts)

Legumes

Black beans (1/2 cup): 8g

Chickpeas (1/2 cup): 7g

Edamame (1/2 cup): 10g

Lentils (1/2 cup): 9g

Peanuts (1/4 cup): 9g

Soymilk (1 cup): 6-11g

Firm tofu (1/2 cup): 20g

 

Nuts and seeds

Almonds (1/4 cup): 7g

Cashews (1/4 cup): 6g

Chia seeds (1/4 cup): 6g

Flaxseeds (1/4 cup): 7g

Pumpkin seeds (1/4 cup): 10g

Tahini (2 tbsp): 5g

Sunflower seeds (1/4 cup): 7g

 

Grains

Slice of rye bread: 3g

Buckwheat (1/2 cup): 3g

Oatmeal (1/2 cup): 3g

Quinoa (1/2 cup, cooked): 4g

Brown rice (1/2 cup cooked): 2g

Spaghetti (1/2 cup): 4g

Spelt (1/2 cup): 6g

 

Vegetables

Avocado (7 oz; about 1 medium): 4g

Broccoli (cooked 1/2 cup): 2g

Corn (1/2 cup cooked): 2g

Kale (chopped, 1 cup): 2g

Dried shiitake mushrooms (1/4 cup): 10g

Peas (1/2 cup): 4g

Potato (baked, medium): 4g

 

Take away message: When consuming a plant-based diet, try to make sure your diet is varied, and rich in vegetables, fruit, legumes, whole grains, nuts and seeds. Most people need about 0.8-1.0 g/kg of their body weight per day in protein.

References 

1. Davis B, Melina V. Becoming Vegan: The Complete Reference to Plant-Base Nutrition. Book Publishing Company; 2014 Aug 7.

2. McDougall J. Plant foods have a complete amino acid composition. Circulation. 2002 Jun 25;105(25):e197-.

3. Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. The American journal of clinical nutrition. 1994 May 1;59(5):1203S-12S.

4. Heart and Stroke Foundation of Canada. For vegetarians. Heart and stroke foundation. 2018. Retrieved from http://www.heartandstroke.ca/get-healthy/healthy-eating/specific-diets/for-vegetarians

5. Tome D. Criteria and markers for protein quality assessment–a review. British Journal of Nutrition. 2012 Aug;108(S2):S222-9.

6. World Health Organization/Food and Agriculture Organization/United Nations University. Expert Consultation. Protein and amino acid requirements in human nutrition. WHO Technical Report Series- 935. (World Health Organization/Food and Agriculture Organization). 2007.

7. Gaffney‐Stomberg E, Insogna KL, Rodriguez NR, Kerstetter JE. Increasing dietary protein requirements in elderly people for optimal muscle and bone health. Journal of the American Geriatrics Society. 2009 Jun 1;57(6):1073-9.

8. Millward DJ. Sufficient protein for our elders?. The American journal of clinical nutrition. 2008 Nov 1;88(5):1187-8.

9. Morais JA, Chevalier S, Gougeon R. Protein turnover and requirements in the healthy and frail elderly. The journal of nutrition, health & aging. 2006 Jul 1;10(4):272.

10. Paddon-Jones D, Rasmussen BB. Dietary protein recommendations and the prevention of sarcopenia: protein, amino acid metabolism and therapy. Current opinion in clinical nutrition and metabolic care. 2009 Jan;12(1):86.

2 thoughts on “Common Plant-Protein Myths Debunked

  1. Great article!!! Thanks for sharing your knowledge

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