What is the first question you get when eating a plant-based diet?
How do you get your protein, bro?!
Since most people assume that you can only get protein from animal sources this might seem to be a valid question. However, even without these animal sources, there is no problem covering your daily requirements with plant-based foods. So the question is not if you can get enough protein on a vegan diet but rather how. The following post explains what protein is, why we need it, how much of it we should consume and last but not least the best sources of plant-based protein.
What is protein and why do we need it?
Protein is a nutrient that the body needs to grow and maintain itself. Next to water, protein is the most plentiful substance in our body. Just about everyone knows that muscles are made of protein. Actually, every single cell in the body has some protein. Furthermore, other important parts of the body like hair, skin, eyes, and body organs are all made from protein. Many substances that control body functions, such as enzymes and hormones, are also made from protein. Additional functions of protein include forming blood cells and making antibodies to protect us from illness and infections.
Proteins can also be used as energy; however, they are not the primary choice as an energy source. For proteins to be used by the body they need to be metabolized into their simplest form, amino acids. This means that if your energy requirements are not met the body will start to draw upon its muscle tissue as a source.
There have been 20 amino acids identified that are needed for human growth and metabolism. Twelve of these amino acids (eleven in children) are termed nonessential, meaning that they can be synthesized by our body and do not need to be consumed in the diet. The remaining amino acids cannot be synthesized by the body and are described as essential meaning that they need to be consumed as food. The absence of any of these amino acids will compromise the ability of tissue to grow, be repaired or be maintained.
What are good sources of plant-based protein?
If you think about protein sources most people think of animal foods, like meat, fish, poultry, eggs, and dairy products. They are also said to be a complete source of protein because animal proteins are much more similar to human proteins. Complete sources of protein contain adequate proportions of all nine essential amino acids (EAA). On the other hand, plant-based protein is said to be incomplete since many sources lack one amino acid or the other.
This might be true if you look at specific foods which might be low in specific amino acids. However, getting a complete amino acid profile on a vegetarian or vegan diet shouldn’t be a problem since I assume most of us combine different foods when they cook. By mixing different plant-based sources you can achieve a complete profile easily. However, it isn’t even necessary to consume the different sources in the same meal, the balance over a day is of much greater importance. The skeletal musculature has a sizeable pool of free amino acids which can buffer low levels of certain amino acids until the next meal.
Combining foods from any two of the following plant groups, in the same meal or during the day, will make a more complete amino acid profile:
- Legumes, such as dry beans, peas, peanuts, lentils, and soybeans
- Grains, such as wheat, rye, rice, corn, oats, and barley
- Seeds and nuts, such as sunflower and pumpkin seeds, pecans, and walnuts1
I prepared the table below to show you an example of how you can combine your food. You can see the values for mg per kg body weight of all nine essential amino acids recommended by the Institute of Medicine (IOM). The middle column shows the daily recommendations for an 80kg person. As a reference, we have a meal of 200 grams of rice with 172 grams of black beans. This single plant-based protein meal would already cover 50 percent or more of most essential amino acids.
EAA requirements and example
|Amino acid||mg/kg body weight||EAA Requirements 80kg person [mg]||Rice + black bean meal|
|Methionine & Cystine||19||1520||41%|
|Phenylalanine & Tyrosine||33||2640||65%|
The meal consists of 487 kcal and a total of 35.8 grams of protein. If we assume a daily calorie intake of 3,000 kcal (light activity) for an 80kg male it isn’t hard to imagine that this person could cover the daily requirements with the rest of the daily meals. Of course, the EAA requirements are based on an average person and will increase with more physical activity. Nevertheless, even if you multiply the daily requirements with a 1.5 activity factor (see my post on the daily calorie intake) the percentage still stays above 30-40% plus we have to keep in mind here that this only represents one meal. If the activity level of our test person increase and his daily energy requirements rise to let’s say 3,500 kcal there is much room for other meals to fill the rest of daily EAA requirements.
Even the amount of lysine, which is the least abundant amino acid found in plant foods, is already covered by 41%.
So as you can see by the example above and studies actually back this up, plant-based protein is not inferior to animal-based protein when combining different plant-based foods. Additionally, there are a lot of benefits associated with a plant-based diet. (Just take look at the China Study which is one of the most comprehensive studies of nutrition or Dr. Michael Greger’s How not to die)
Good sources of plant-based protein
So which foods are best to consume if you follow a plant-based diet and want to get optimal protein intake? The following table shows you a selection of foods that provide high-quality protein (amino acid score > 100). The data was collected on http://nutritiondata.self.com/.
|Food||Protein per 100g|
|Beans (cooked)||15.5 g|
|Chia seeds||16.5 g|
|Hemp seeds||31.6 g|
|Chickpeas (cooked)||14.5 g|
|Pumpkin seeds||24.5 g|
|Flax seeds||18.3 g|
|Quinoa (cooked)||8.1 g|
How much protein do we need a day?
The IOM recommends 0.8 grams of protein per kilogram body weight for adults above the age of 19 years. If you are between 14-18 years this number rises to 0.85 grams.
Since you are reading this blog I would assume that you are not the average person sitting in front of the TV after work but rather switch on your boss mode to regularly engage in movement practice or pump some iron (if not stop reading this and start moving!). So does this 0.8 g/ kg body weight recommendation also apply to people that work out a lot?
Research shows that athletes have a higher demand for protein compared to their sedentary counterparts. It will depend on your individual activity level but with a protein intake of 1.2-2.0 g/kg body weight you should be good to go. A Swiss study also suggests that recommendations between endurance and strength athletes are no longer supported. They suggest a daily intake of 1.5 g/kg body weight which should be adapted by +/- 0.5 grams based on individual circumstances.
Several studies indicate that consuming EAAs between 1-3 hours after your workout is most efficient for optimal muscle growth. Furthermore the higher the quality of the protein the less we actually need of it. Also strength training in general increases the efficiency of use of protein, which also reduces dietary protein requirements.
I personally consume between 100-115 g of protein on training days, so around 1.25-1.4 g/kg of my body weight (80kg), which is approximately the adequate amount for my activity level and body composition. I try to consume 80-85% by whole foods and the rest with plant-based protein powders.
So if you experiment with a plant-based diet and are worry about your protein intake just shoot me an email!
Take care and talk to you soon!
Photo credit: Ulleo, check out some cool pics here.
 Young, V. R., & Pellett, P. L. (1994). Plant proteins in relation to human protein and amino acid nutrition. The American journal of clinical nutrition, 59(5), 1203S-1212S.
 Bergström, J., Fürst, P., & Vinnars, E. (1990). Effect of a test meal, without and with protein, on muscle and plasma free amino acids. Clinical Science, 79(4), 331-337.
 Nutrition Data (Black Beans): http://nutritiondata.self.com/facts/legumes-and-legume-products/4284/2
 Nutrition Data (White Rice): http://nutritiondata.self.com/facts/cereal-grains-and-pasta/5712/2
 Millward, D. J. (1999). The nutritional value of plant-based diets in relation to human amino acid and protein requirements. Proceedings of the Nutrition Society, 58(02), 249-260.
 Phillips, S. M. (2006). Dietary protein for athletes: from requirements to metabolic advantage. Applied physiology, nutrition, and metabolism, 31(6), 647-654.
 Phillips, S. M. (2012). Dietary protein requirements and adaptive advantages in athletes. British Journal of Nutrition, 108(S2), S158-S167.
 Wilson, J., & Wilson, G. J. (2006). Contemporary issues in protein requirements and consumption for resistance trained athletes. Journal of the International Society of Sports Nutrition, 3(1), 7.
 Phillips, S. M. (2004). Protein requirements and supplementation in strength sports. Nutrition, 20(7), 689-695.