They can even make you smarter

What are fats?

Fats, alongside carbohydrates and proteins, are basic nutrients our body obtains from food. They are characterised by a high energy density. At roughly 9 kilocalories per gram, they provide more than twice the energy of proteins or carbohydrates. Because of this property, fats were long viewed negatively—especially regarding weight gain. But this perspective is limited, as the importance of fat goes far beyond calorie content.

A distinction is made between animal and plant fats, which differ noticeably in composition. Animal products such as butter, meat or cheese tend to contain more saturated fatty acids, while plant sources like nuts, seeds, avocados and vegetable oils are often rich in unsaturated fatty acids. Fatty fish such as salmon or mackerel play a special role: although animal-derived, they contain many health-promoting omega fatty acids.

What functions do fats have in the body?

Fats perform numerous vital tasks in the human body that extend well beyond their role as energy providers. Due to their high calorie density, they are a particularly efficient energy source and also allow excess energy to be stored as adipose tissue. This reserve fat is available during prolonged physical exertion or periods of limited food intake.

In addition, fats are essential for the absorption of fat-soluble nutrients. Only when consumed with fat can the body utilise vitamins A, D, E and K from food. They fulfil important functions, for example for cell protection, the immune system, blood clotting and bone health.

Another central aspect is the supplyof essential fatty acids. Because the body cannot produce them, they must be obtained through the diet. They are necessary for the formation and functionality of cell membranes, influence lipid metabolism and help regulate inflammatory processes as well as lower elevated cholesterol levels. In particular, omega‑3 fatty acids have anti-inflammatory effects and improve the flow properties of the blood.

Fats are also important building blocks of cell structure. The membranes of all body cells are largely composed of lipids, which ensure their stability and control the exchange of substances. Fats also play a decisive role in the formation of certain hormones: for example, steroid hormones such as oestrogen, testosterone or cortisol are derived from cholesterol and regulate many metabolic processes. Additionally, adipose tissue produces hormone-like substances such as leptin, which influence feelings of hunger.

Fats are also important for the body’s external protective function. Under the skin they act both as insulation against cold and as padding for sensitive internal organs such as the kidneys or liver. Furthermore, fats are carriers of fat-soluble flavour compounds. Many aromas only fully develop in the presence of fat, which is why fatty foods are perceived as particularly flavourful. This explains why very low-fat diets are often considered less tasty.

What are saturated and unsaturated fatty acids?

Fatty acids are the central building blocks of fats. Depending on their chemical structure, they differ significantly from one another, particularly in terms of saturation. This property affects not only the physical characteristics of the fat but also its effects in the body.

Saturated fatty acids have a relatively rigid structure. That is why they are usually solid at room temperature, as is the case with butter or coconut fat. They are found primarily in animal products such as meat, sausages, cheese and cream, but also in some plant fats like palm oil. The body can synthesise them, so they do not necessarily need to be supplied through the diet. However, regularly consuming too much can worsen blood lipid profiles, particularly the proportion of so‑called “bad” LDL cholesterol. This can increase the long‑term risk of cardiovascular disease.

Unsaturated fatty acids have a structure that makes them more flexible. Therefore they are usually liquid at room temperature, such as olive oil. A distinction is made between monounsaturated fatty acids, like those in olive oil, and polyunsaturated fatty acids, which are found for example in nuts, seeds or fatty fish. Among polyunsaturated fatty acids are the valuable omega‑3 and omega‑6 fatty acids, which the body cannot produce itself. They must be obtained from the diet and play an important role for a healthy heart, brain and cells.

Trans fatty acids are a special case. Although chemically classified as unsaturated fatty acids, they possess an altered spatial configuration. This can arise from industrial processes or intense heating. This form has unfavourable health effects, as it worsens blood lipid levels and can promote inflammation.

Can I do without fat?

A complete avoidance of fat in the diet is not recommended, because fat plays an indispensable role for health. Many diets advocate reduced fat intake, for example as part of a low‑fat regimen, to lower daily calorie intake and thereby lose weight. In such cases it is recommended to replace high‑fat foods with lower‑fat alternatives and to prefer low‑fat cooking methods such as steaming or grilling.

However, a very low‑fat diet can also have disadvantages. If fat is restricted too much, there is a risk of inadequate supply of essential fatty acids and fat‑soluble vitamins such as A, D, E and K.

Rather than avoiding fat entirely, a balanced approach should be sought. A conscious choice of foods with as few hidden fats as possible, but with sufficient sources of “good” fats, is more sensible and sustainable than strict reduction. In short: completely avoiding fat is not only unnecessary, it can even carry health risks.

Oils and fats: what is the difference?

The key difference between oils and fats lies in their consistency at room temperature: oils are liquid, fats are solid or spreadable. This property depends on the melting point, which is determined by the types of fatty acids present. Oils consist predominantly of unsaturated fatty acids, which favour a liquid structure. Solid fats, by contrast, generally contain a higher share of saturated fatty acids, making them firmer at normal temperatures.

Regardless of whether the source is plant or animal, olive, rapeseed or sunflower oil are classed as oils, while butter, coconut fat or margarine are considered solid fats. Some plant oils, for example from oil palm or coconut palm, are also solid at cooler temperatures, even though they are technically oils. They have not been hydrogenated but are naturally spreadable in our latitudes.

The food industry can also deliberately hydrogenate liquid oils to make them spreadable. This produces trans fats, which can be problematic from a health perspective. Corresponding indications appear on ingredient lists under terms such as “hydrogenated fat” or “hydrogenated”.

How much fat does my body need per day?

Daily fat requirements depend primarily on individual energy expenditure. This is determined by factors such as height, sex, age and activity level. Generally, fat should make up about 20 to 30 percent of total calorie intake. Depending on energy needs, this corresponds to a recommended fat amount of 60 to 80 grams per day. With a moderate calorie intake of 1'800 kilocalories, around 60 grams of fat are sensible, while with a higher intake of about 2’000 kilocalories up to 70 grams may be appropriate.

However, what matters is not only the amount of fat but above all the quality. Unsaturated fatty acids, found for instance in vegetable oils, avocados, seeds and fatty fish, are particularly healthy since they support the heart and metabolism. Saturated fats from animal products should be limited to a maximum of ten percent of calories. Trans fats from highly processed foods are particularly harmful and should be avoided entirely.

How to benefit from fats: practical tips

• Include a thumb‑sized portion of fat per meal, for example olive oil in a salad, salmon or nuts. This promotes the absorption of fat‑soluble vitamins A, D, E and K.
• Both in a low‑carb and a Mediterranean diet, reduce mainly simple sugars and highly processed carbohydrates rather than fat. Choose high‑quality vegetable oils rich in healthy unsaturated fatty acids, such as flaxseed, hemp or walnut oil.
• When shopping, look for cold‑pressed, unrefined oils in dark bottles, as they are particularly rich in unsaturated fatty acids and sensitive to light and heat.
• Use polyunsaturated oils like flaxseed or walnut oil only cold, for instance added to salads, dips or steamed vegetables, because they oxidise quickly when heated.
• Avoid hidden fats in ready meals, snacks and sweets by opting for fresh, unprocessed foods.
• For frying, a teaspoon of oil spread with a brush in the pan is sufficient. This saves calories without affecting flavour.
• Cook foods in the oven, wok or steamer rather than frying to keep the fat content of your meals low without sacrificing enjoyment.
• Prefer plant‑based spreads made from nuts, lentils or avocado instead of cheese or cold cuts on bread to reduce intake of saturated fats and increase fibre.
• Also eat fatty fish regularly, such as salmon, sardines or herring, to meet your omega‑3 needs. These are important for heart health, the brain and for reducing inflammation.
• Prefer foods with plant‑based dietary fats, like flaxseed or rapeseed oil, as they are rich in the healthy alpha‑linolenic acid (omega‑3) and low in the pro‑inflammatory linoleic acid (omega‑6). This helps lower cholesterol and avoid unhealthy fats.
• Read ingredient lists on processed foods carefully to spot hidden fats, especially hydrogenated fats or palm oil, and avoid them when possible.

Avoiding fat does not automatically mean living healthily. Rather, it’s about integrating the right fats in the appropriate amounts into your diet.