Proteins are molecules within the body made up of amino acids. They are also known colloquially as proteins.
In the course of digestion, the proteins ingested with food are broken down into amino acids. New proteins can then be assembled from this.
As an important part of every cell, proteins often make up more than half the dry weight of a cell. Muscles, heart, brain, skin and hair are mostly made up of proteins.
Proteins perform important functions in the body. For example, they are an indispensable part of the immune system because they act as antibodies.
A subgroup of proteins are collagens, which give the skin structure. Proteins are also responsible for transporting oxygen in the blood, for blood clotting, the contraction of muscles and much more.
A protein deficiency can manifest itself, for example, in muscle weakness, hair loss, or growth disorders. In extreme cases, which fortunately are extremely rare in Europe, hunger oedema develops. This is water retention that occurs mainly in the stomach and leads to the characteristic 'hunger stomach'.
The German Nutrition Society (DGE) recommends that adults consume 0.8 grams of protein per kilogram of body weight. This need is increased for pregnant women, children and adolescents.
Eggs, meat and fish, among others, are viewed as particularly protein-rich foods. The prevailing opinion for a long time that animal proteins can in principle be processed better than plant-based proteins has now been refuted.
The proportion of the respective amino acids is decisive for the utilization. Vegans can get the proteins they need from legumes and nuts.
If you want to build muscles, you may look for protein-rich foods: 'For performance-oriented people from the endurance and weight training sectors, depending on the duration and intensity of the training, an increased protein intake of 1.2 - 1.6 g/kg body weight can be beneficial in terms of muscle strength or muscle mass and muscle regeneration.'(deutsche-apotheker-zeitung.de)
However, this recommendation can't simply be applied to all types of sports and/or athletes. It also depends on whether the focus is on building or maintaining muscles. Endurance athletes, for example, are sometimes more dependent on carbohydrates rather than proteins. For them, the much lower DGE recommendations could be sufficient in individual cases.