If you have decided on health or ethical reasons not to eat animal food, sooner or later, someone will face you with the question of how you satisfy your daily protein requirements. If you believe the opinion of the general public, plants do not seem to be suitable for covering your daily protein requirements. I dare to challenge this opinion and will explain in this article why I think so. You will also learn how you can easily cover your daily protein requirements with a plant-based diet.
Proteins are essential for life because they fulfill a large number of crucial tasks. We cannot survive without them. Every cell in our body is made up of structural proteins. Proteins are part of the immune system and protect our body from intruders such as viruses and bacteria. As components of hormones, proteins control our body, and as enzymes maintain our metabolism. Besides, transport proteins ensure that nutrients reach the right places in the body (e.g., ferritin as a transport protein for iron).
Proteins are complex structures made up of amino acids. There are 20 different amino acids, of which eight are essential, two are semi-essential, and the remaining ten are non-essential. Our body cannot produce essential amino acids from other nutrients itself, so they must be ingested through food.
Semi-essential amino acids can become essential under special living conditions (age, disease, pregnancy, physical activity, growth phase, etc.). Under normal circumstances, our body can produce them in sufficient amounts.
Regarding non-essential amino acids, there is no need to supply them through food as our body can produce them in sufficient amounts out of other nutrients.
The following table gives you an overview of the different amino acids.1
|Leucine||Histidine||Aspartate / Asparagine|
|Lysine||||Cysteine / Cystine|
|Methionine||||Glutamate / Glutamine|
The biological value (BV) indicates the quality of proteins contained in food in comparison to that of our body. Combinations of proteins are also known as an amino acid profile or aminogram.
The presence or absence of the essential amino acids plays a decisive role. If a food contains all essential amino acids, the protein contained is of high quality. The body can make optimum use of the dietary protein and convert it into its protein.
As a reference food, the chicken egg was determined sometime, which with a BW of 100, is practically identical with our body's protein.
With a few exceptions, plant-based foods generally have a lower biological value than animal-based foods because a piece of meat is physiologically closer to humans than a grain of wheat.
The following table gives you an overview of some foods and their biological value.2
|Food||Biological value (BV)|
|Rye flour||76 - 83|
|Wheat flour||56 - 59|
|Hemp protein||87 - 104|
As you can see, not all plant-based foods are inferior to animal-based foods (e.g., quinoa compared to beef). Thus it can already be said that a sufficient supply of proteins appears to be possible with a vegetable diet.
If a food lacks one or more essential amino acids, or if they are not present in the optimal quantity, the biological value decreases. The low biological value does not mean the food itself is of low quality regarding other nutrients, which is influenced by many different factors, such as vitamin and mineral content, phytochemicals, origin, cultivation, and ripeness. At the moment, we are only talking about the quality of proteins or, more precisely, the quality of the composition of proteins.
It is possible to enhance a low biological value by combining foods, even if the foods combined have a low biological value itself. For example, take soy and rice. Because both are missing the same or different essential amino acids or they occur in varying concentrations, both foods have a biological value of less than 100. If both foods are added together in one meal, the amino acids complement each other and a better amino acid profile results than that found in whole eggs.
The following table shows some other very good combinations of plant-based foods.2
|Food combinations||Biological value (BV)|
|85% rice and 15% yeast||118|
|55% soy and 45% rice||111|
|55% potatoes and 45% soy||103|
You may be wondering how a biological value of more than 100 is possible. As the chicken egg is the reference, an amount more than 100 is simply an excess of essential amino acids compared to the egg. This excess affects the amount of dietary protein that must be consumed to cover the recommended daily intake.
Here is an example. If you covered your protein requirement with foods that all have a biological value of 100, the minimum protein requirement would be 0.5 grams per kilogram body weight per day. If you would select meals with a biological value of 136 by combining 65% potatoes and 35% egg, then the minimum protein requirement would sink to 0.4 gram per kilogram body weight and day1.
With the right mix, a sufficient protein supply is also possible with a plant-based diet.
To take advantage of the principle of a supplementary value, you need to know which (plant-based) foods contain proteins. The following table will help you to make your choice. The information in brackets corresponds to the protein content per 100 grams of the food. To support you in your daily meal planning, I've categorized the foods into meals. This is only a suggestion and can be changed as you like.
Lunch and dinner
In general, legumes (lentils, peas, chickpeas, beans, soybeans, peanuts), nuts, seeds, potatoes, and grains are good sources of protein and are ideal for combining. Hemp seed or hemp protein is excellent as a single protein, as it contains all essential amino acids in optimal amounts.
If I had to create a ranking of protein-rich, plant-based foods, it would be the following.
It is no problem to cover your daily protein requirements with a plant-based diet, even if you exercise a lot or be an athlete. A diversified choice of food is essential, which is not only crucial concerning protein quality, but also for a healthy and balanced diet in general. If you eat a varied diet, you do not have to worry about the protein supply as it comes along.
I hope this article has given you some answers to your questions about plant-based and animal-based proteins. If you are missing something or want more information on a topic, please let me know with a comment. I am looking forward to it.
If you are looking for inspiration, have a look at my Instagram profile on nutrition. I also recommend you check out the brilliant documentary "The Game Changers" about a plant-based diet in sports.