The key building blocks for fitness and well‑being

What are proteins?

Proteins, also called protein, are one of the three essential macronutrients alongside fats and carbohydrates. Unlike the other two nutrients, proteins are not primarily responsible for energy production in our bodies.

Proteins are involved in a wide range of vital metabolic processes. Their structure is remarkable: proteins are made up of amino acids chemically linked together. These amino acids form long, flexible chains known as peptide bonds. But proteins are much more than long chains of cellular material. It is now known that protein structures also contain precisely constructed, movable parts that enable specific chemical reactions.

Why does our body need proteins?

Proteins are extremely versatile, which makes their importance for our organism more complex than it appears at first glance. They are not only responsible for building up and breaking down cells, but also play a key role in communication between groups of cells. These varied functions can be described by different types of proteins.

Structural proteins give cells their shape. Well‑known examples include collagen, elastin and keratin. Collagen is particularly important because it occurs in the skin, connective tissue and in joints, ligaments and tendons, supporting their normal function. Transport proteins, on the other hand, are responsible for transporting certain substances such as lipids or oxygen. Typical members of this group are myoglobin, albumin and hemoglobin. Transport can occur within a cell, nearby or, in rare cases, at a distance.

Storage proteins help the body store vital substances. A well‑known storage protein is ferritin, which stores iron. Contractile proteins enable muscle contraction and thus movement, coordination and stretching. This group includes myosin, actin and dynein. Protective proteins support the body’s defense mechanisms by, for example, forming antibodies for immune defense or promoting blood clotting through fibrinogen.

Some hormones are also proteins. These so‑called protein hormones such as insulin and ghrelin play regulatory roles in various life processes. Insulin regulates blood sugar levels, while ghrelin controls hunger and satiety. Enzymes, most of which are also proteins, act as biocatalysts and trigger specific chemical reactions in the body.

How are proteins constructed and structured?

Proteins are characterized both by their structure and by their diverse functions in the body. Chemically, they are built from amino acids. Amino acids are compounds made of carbon, hydrogen, oxygen and nitrogen. Some amino acids also contain sulfur.

There are several hundred different amino acids in nature. The human body, however, uses only 20 specific amino acids to build protein. These are known as proteinogenic amino acids. Some of these amino acids can be produced by the body itself. Others must be taken in daily through the diet because they are essential for life. These are called essential amino acids.

The eight essential amino acids are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. This particular composition and the need to obtain certain amino acids from food underline the central role of proteins for our metabolism and the construction of our bodies.

What are the best protein sources – animal and plant?

With a balanced diet that includes both animal and plant foods, protein requirements can be easily met. Animal protein is better utilized by the human body because its structure and amino acid composition are more similar to human protein. This higher biological value means that less animal protein is needed to meet daily protein requirements. Animal sources include meat, fish, eggs and dairy products. However, these foods often contain unhealthy fatty acids and can raise cholesterol levels.

A practical tip to improve the biological value of protein is to combine animal and plant protein sources. This can be achieved with dishes such as potatoes with egg, cereals with milk or potatoes with dairy products. Such combinations make the diet biologically higher quality while reducing the intake of fatty substances, cholesterol and purines, while providing complex carbohydrates, fiber and fewer calories.

Plant protein sources are found in foods such as bread, cereals, vegetables, legumes, soy and nuts. Although the body cannot utilize plant protein as efficiently as animal protein, plant foods have the advantage of being low in saturated fats, purines and cholesterol.

How much protein does a person need?

The daily protein requirement of a person can generally be met through a balanced diet. As a rule of thumb, the body needs about one gram of protein per kilogram of body weight. For a 75 kilogram person, this corresponds to about 75 grams of protein per day.

Older and ill people need a little more, about 1,2 bis 1,5 Gramm pro Kilogramm, um die Muskulatur zu erhalten. Auch Leistungssportler und Schwangere haben einen erhöhten Bedarf. Bei Übergewicht orientiert sich der Bedarf am Normalgewicht, z.B. bei 75 Kilogramm Körpergewicht und einer Körpergrösse von 1,65 Meter wären das etwa 65 Gramm pro Tag.

Regardless of training goals, recommendations often range from 2,0 to 2,5 grams of protein per kilogram, especially for people with low body fat. A protein‑rich diet also promotes satiety and weight loss, and higher protein intake combined with resistance training has no negative effects.

What happens if the body takes in too little protein?

Protein deficiency can cause various symptoms. Often a protein deficiency manifests as muscle weakness and muscle wasting. This leads to a loss of muscle mass, which can impair physical performance. Children are particularly affected, where protein deficiency can delay normal growth and lead to weight loss.

Another sign of insufficient protein supply is oedema, i.e. fluid accumulation in tissues. These swellings often occur in the legs, ankles and face. Hair loss and brittle nails can also indicate a deficiency, as protein is an important component of hair and nails.

How to add more protein to your diet: useful tips

• Make a list of your preferred protein sources. This gives you a clear overview for shopping and meal planning and helps you choose foods high in protein.
• Choose lean protein sources such as chicken breast, turkey or fish to get protein without additional saturated fats. For vegetarians, tofu, tempeh and legumes are good alternatives.
• Top your meals with protein‑rich ingredients. Sprinkle pumpkin seeds, sunflower seeds, chia seeds or almonds over your dishes to boost their protein content.
• Choose protein‑rich snacks. Hard‑boiled eggs, nuts, Greek yogurt or edamame make nutritious snacks.
• Protein shakes are a quick and easy way to meet your protein needs. Choose a high‑quality protein powder such as whey protein, which provides about 17 g of protein per 28 g serving. Mix it with plant milk, a banana and some peanut butter for a nourishing drink.
• Replace white rice with quinoa or whole grain rice, which contain more protein. Replace white bread with whole grain bread or bread with higher protein content, e.g. protein bread.
• Bake with protein powder. Replace 30–50% of the flour in baking recipes with protein powder to make protein‑rich baked goods.
• Include pistachios in your diet. They contain about 18 g of protein per 100 g and are suitable as a snack or side dish.
• Add spirulina to smoothies; it is a concentrated protein source and can be added to green smoothies.
• A balanced diet with lentils, beans and chickpeas can help athletes consume adequate amounts of bodily protein and promote protein biosynthesis.
• It is recommended to use Parmesan for seasoning. It contains 35 g of protein per 100 g. Sprinkle some Parmesan over your dishes to enhance both flavor and nutritional value.
• Track your protein intake with an app or diary. This helps monitor and adjust daily needs.

Proteins perform essential functions in our bodies and are indispensable for many biological processes. By consciously selecting and combining foods, everyone can ensure that daily protein needs are met and thereby support overall well‑being.