Protein sources: These foods are packed with protein

Eiweißquellen: Diese Lebensmittel stecken voller Proteine

Food containing protein is an important part of a balanced and healthy diet, especially as a structural and building material for the human body. Because protein-rich food is not only healthy and keeps you full for longer, but also boosts the metabolism, supports muscle building and ultimately helps with weight regulation.

Proteins are therefore among the most essential nutrients for the human organism. Unfortunately, many people do not even know which foods contain the concentrated protein power and, above all, what the differences are between vegetable and animal protein sources. So that you can use all the benefits of protein sources for yourself through a balanced diet and a targeted choice of food, we will explain all the important points about protein sources in the following.

the essentials in brief

  • Protein is an important part of a balanced and healthy diet, which is not only responsible for building muscle, but also for important metabolic processes.
  • There are both animal and vegetable sources of protein. The quality or the biological value of the protein source is of particular relevance in the differentiation.
  • With the different protein sources, the combination of protein products is an advantage, since it increases the biological value of the protein sources enormously and you can get the best out of the protein sources for your health.

Background: What you should know about protein sources

You can find all the important information on the subject of protein sources, from their effects on our body to the best protein-rich foods and alternative sources of protein, in our guide.

Why is protein important in the diet?

Proteins are macronutrients made up of small building blocks called amino acids. Every cell in the human organism consists of these chained protein molecules, with these proteins even making up 10% of our brain and 20% of the heart, many muscles and the liver.

In addition, the valuable proteins transport many vital substances so that they can help the human body with metabolic processes, regeneration, muscle building or digestion. Unfortunately, humans cannot produce these protein molecules themselves, which is why they have to rely on protein-rich foods.

As an adult, you can produce 11 of the 20 amino acids on your own.

Humans need a total of 20 different amino acids to build proteins so that all relevant processes, for example for growth or metabolism, work. The organism must therefore absorb the remaining 9 amino acids through food, whereby these amino acids are described as indispensable. If there is no regular supply of amino acids, protein deficiency can occur. (1).

The respective requirement for covering the vital 9 amino acids can be achieved with a balanced diet. A full-grown human organism between the ages of 19 and 65 needs about 0.8 g protein/kg body weight per day. For adults over the age of 65, the DGE recommends an estimated value of 1.0 g/kg body weight per day (2).

What are protein sources?

All foods that contain protein are called protein foods. A food is referred to as a source of protein if 12 percent of the total energy value of the food can be related to the protein content. If food has a very high protein content, i.e. at least 20 percent of the total calorific value of the food is due to protein, then the food is described as high in protein (3).

What is a protein diet?

With a protein-rich diet, the consumer focuses primarily on an increased protein intake and reduces his carbohydrate intake accordingly. About 50% of the daily calorie requirement is covered by protein. After that come fats with about 35% and then carbohydrates with 15%. Athletes who want to build muscle often follow a protein-rich diet.

Why is the quality of protein sources so important?

When classifying the quality, the biological value of a protein source plays an important role. The number and type of protein building blocks in the respective food, i.e. the amino acids, distinguish how high the biological value of the food is (6).

The 9 essential amino acids, which the human organism absorbs through food, ultimately determine the quality or the biological value of the respective protein source. Whether a food is labeled as a complete, incomplete or combined protein source depends on how many of the 9 essential amino acids the food contains. (4)

The food with the highest protein quality is the chicken egg.

Animal protein sources are generally considered to be of higher quality than vegetable protein sources because they have more essential amino acids. The combination of animal and vegetable protein sources can significantly increase the protein quality in the human body (5).

  • Complete protein sources: This type of protein source has all 9 essential amino acids. Complete sources of protein can be found in animal foods in particular, such as dairy products, meat, fish or eggs. However, there are also plant-based protein sources that contain complete proteins, such as hemp, chia seeds, quinoa, or soy products (5).
  • Incomplete protein sources: These protein sources lack one or more of the 9 essential amino acids, which is why the biological value is lower. The sole supply of incomplete protein sources would not be sufficient to provide the body with complete protein. Examples of incomplete proteins in this case would be legumes, nuts and seeds, and vegetables (5).
  • Combined protein sources : In order to meet the daily protein requirements, it is recommended to combine the incomplete protein sources, which can result in a complete protein source. In addition, the protein quality is increased when animal and vegetable proteins are combined. Possible combinations would be legumes with nuts or grains, such as whole grain bread with hummus or beans with corn (6).

Above all, however, it is important to ensure that you don't just eat complete proteins, but combine them again and again. A balanced and healthy diet is only possible with a combination of vegetable and animal protein sources. In addition, the body can utilize the supplied protein sources much better through the combination (6).

What is the difference between animal and vegetable protein sources?

Those proteins that correspond particularly closely to human proteins due to the chaining of the amino acids can be processed and absorbed more quickly by the body. In particular, the amino acid structure of animal proteins is similar to that of human proteins.

In principle, however, both animal and plant-based protein sources are considered suitable to cover protein requirements, since all essential amino acids are contained in plant-based and animal-based foods. It is also important here, whether animal or vegetable protein, to pay attention to the biological value of the products. Because this ultimately decides how quickly proteins can be converted in the body.

In order to achieve the highest possible biological value, it should also be noted when distinguishing between animal and vegetable protein sources that you can get the best out of your personal health with the clever combination of protein-rich foods.

The animal protein sources

Due to the high amount of essential amino acids, animal protein sources are particularly interesting for athletes who want to build muscle. Therefore, animal proteins generally have a very high protein quality.

  • High protein quality
  • higher quality
  • More expensive
  • High environmental impact
  • Cardiovascular problems
  • Few other nutrients

The disadvantages of animal proteins are being worked out more and more clearly in studies. It has been found that animal proteins contain a large amount of cholesterol and unfavorable saturated fatty acids and hardly any phytochemicals, fiber or folic acid (7).

Animal and vegetable sources of protein

Animal proteins are particularly popular with athletes. However, there are also certain disadvantages to consuming animal protein sources. (Image source: Humphrey Muleba / unsplash)

Furthermore, more and more studies point to the risk of cardiovascular diseases in connection with animal proteins (7). In addition, the moral component of environmental pollution and the exploitation of animals is becoming increasingly important.

Groceries Protein content per 100 g
pork loin 22g
chicken breast 24g
lamb chop 25g
Trout 24g
tuna 22g
harzer cheese 27g
chicken egg (whole egg) 13g

Finally, it should be pointed out that it is not advisable to eat only animal protein sources. In two long-term studies on this topic, it was found that the sole intake of animal protein sources is associated with a higher risk of death than that of vegetable protein sources (7).

The vegetable sources of protein

Vegetable sources of protein are often incomplete. This is because most plant proteins lack 1-2 essential amino acids for the protein source to be of high quality. This is also the reason why vegetable protein sources are still not so popular with athletes.

  • Contains additional nutrients
  • cheaper
  • Less environmental impact
  • Good for health
  • Incomplete source of protein

In contrast to animal protein sources, however, vegetable ones are rich in unsaturated fatty acids, are full of vitamins and minerals and at the same time have much more dietary fiber and secondary plant substances. In addition, they are always cholesterol-free and keep you full longer due to the carbohydrates. As a result, vegetable protein sources have a particularly good effect on our health.

Special protein source

A very special vegetable source of protein is the alga Spirulina. With its enormously high protein content, it is considered a superfood. (Image source: Anaïs CROUZET / unsplash)

Nevertheless, it should be pointed out that essential amino acids are not sufficient in phases of particularly high demand, such as during growth or in competitive athletes. Due to the lower protein quality of vegetable protein sources compared to animal protein sources, the protein requirement in such phases cannot be covered exclusively by vegetable protein (8).

Groceries Protein content per 100 g
quinoa 14g
oatmeal 13g
hemp seeds 37g
pumpkin seeds 24g
Spirulina 57g
peanuts 25g
lenses 24g

In addition, a high biological value can also be achieved with vegetable protein sources by combining several vegetable proteins with one another. This allows the missing amino acids to be supplemented, which increases the quality enormously. With a varied diet, this combination of protein-rich foods is already present (9,10).

For whom is a high-protein diet suitable?

According to the German Nutrition Society, a healthy adult should consume an average of 0.8 grams of protein per kilogram of body weight every day. That's around 60 to 70 grams of protein per day for an adult male and around 50 grams for an adult female (2).

competitive athlete

Above all, strength and endurance athletes or competitive athletes have to adjust their diet to their increased protein requirements. Muscles need to be regenerated and built up again after intensive training. Since around 20% of muscle consists of protein, it is advisable to adjust protein intake to repair, build and maintain muscle (13).

A protein-rich diet is also ideal for losing weight, since there are usually hardly any carbohydrates in the protein sources. Nevertheless, you should not combine a protein-rich diet with other diets, such as 16/8 intermittent fasting , otherwise the body will have too low an energy level.

For whom is a high-protein diet suitable?

Above all, strength and endurance athletes or competitive athletes need a lot of protein. Since the muscles are constantly being used, they also need constant regeneration from the additional sources of protein. (Image source: Victor Freitas / unsplash)

Post-exercise nutrition is particularly important. Various studies now seem to have designed a guideline for the protein intake of strength athletes, which is why 1.6 g of protein per kg of body weight per day applies. For a 100 kg strength athlete, this would be 160 g of protein per day according to the rule of thumb. However, this rule of thumb only applies to strength athletes, such as powerlifters, track and field athletes or bodybuilders (14).

Elderly and sick people

Older people are often affected by a protein deficiency, as they often suffer from over-acidification of the body. As a result, the body loses muscle and bone mass, especially as we age.

In order to prevent this muscle loss, it is relevant for people over the age of 70 to consume around 1 g of protein per kg of body weight every day. Regular exercise can also protect bones and muscles (11). Sick people, people who are overweight or pregnant women also need a higher protein intake.

Vegans and vegetarians

In a vegetarian or vegan diet, all foods are avoided, which can lead to an undersupply of important nutrients.

In addition to vitamin B12, the intake of protein is particularly critical. This is why vegans and vegetarians also have an increased intake of plant-based, combined protein sources (12,15,16).

What are the protein sources of the future?

How can you combine a healthy diet with protein sources and sustainable protein production? The German Institute for Human Nutrition Potsdam-Rehbrücke (DIfE), together with the Potsdam Institute for Climate Impact Research and other member institutes, have now analyzed how the protein requirements of the growing world population can be met in such a way that the environment and human health benefit equally.

The production of protein-rich food often not only results in high emissions, but also in the loss of biodiversity and overexploitation of water resources. However, animal and vegetable proteins are essential for a balanced diet and human health. Therefore, the search for alternative protein sources is relevant for the future.

With their position paper "Sustainable food production and healthy nutrition", the researchers want to throw research-leading questions into the discourse and find out what possibilities and strategies there are to combine the ecological aspect of sustainability with health-promoting food security. The first solution approaches look like this (17).

  • More sustainable food: The quality of the animal protein sources hardly differs, but if you look at the ecological footprint, the differences are enormous. Therefore: a switch to more sustainable animal foods such as from beef to chicken (17).
  • Combine sensibly : The researchers also point to the targeted combination of plant-based protein sources. A high biological value can also be achieved in this way (17).
  • Switching to strange foods: The proteins in dried insects are highly concentrated, which means you need fewer quantities. There are also 2,111 species of insects that are digestible for humans and are also packed with impressive nutrients. For example, 50 grams of mealworms are enough for the daily protein requirement (18).

Furthermore, there are numerous other possibilities for ecologically sensible protein production. For example, there are alternatives such as growing legumes in your own garden or converting mono-aquaculture into integrated production systems. The excrement from the fish farm is used to grow plants.

In this context, it is relevant that the population's awareness and interest in the ecological footprint in connection with healthy protein intake is growing. Only in this way is a future with alternative protein sources possible.


Proteins are one of the most elementary building blocks of the human organism and take on special tasks, such as growth or metabolism. Humans can only produce proteins on their own to a limited extent, which is why they also have to cover their protein requirements with food.

Protein sources are therefore of great relevance for a balanced and healthy lifestyle. Both animal and vegetable protein sources provide important proteins for the human body, with the combination of different protein sources in particular ensuring a high biological value. However, an excessive protein-rich diet should also be avoided. The same applies here: Balance is the key to happiness.


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  2. German Society for Nutrition (DGE) (2017): Reference values ​​for nutrient intake - protein Source
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