Not all fats are created equal – a differentiated view of healthy and problematic fat sources

Fats have played an ambivalent role in nutritional science discussions for decades. While they fulfill an indispensable physiological function as energy sources, building blocks for cell membranes, and carriers of fat-soluble vitamins, they are also suspected of promoting inflammatory processes or metabolic disorders—depending on their source and processing. 

This article classifies different fat sources from a biochemical and nutritional perspective and highlights both their potential benefits and risks in the context of a balanced diet.

Functions of fats in the human organism 

Along with carbohydrates and proteins, fats are macronutrients and are involved in, among other things: 

• the provision of energy (9 kcal per gram),
• the absorption of fat-soluble vitamins (A, D, E, K),
• the synthesis of steroid hormones,
• the formation and stability of biological membranes,
• immunological and neurological processes.

However, the physiological effects vary considerably depending on the fatty acid structure, origin and degree of processing.

Traditional fat sources and their nutritional significance

butter 

Butter is one of the oldest sources of fat in the human diet. It not only provides energy but also a variety of bioactive components. In addition to saturated fatty acids, it contains significant amounts of vitamin A (important for vision and immune function), vitamin D (bone metabolism), and vitamin K2 (calcium regulation).

Particularly noteworthy is the content of short-chain butyric acid (butyrate) , which is also produced in the large intestine through fermentation and plays a central role in the intestinal mucosa and the immune system. Studies suggest that butyrate may have inflammation-modulating and metabolically beneficial properties.

Butter also contains traces of conjugated linoleic acid (CLA), a fatty acid that has been associated with anti-obesity and anti-carcinogenic effects in animal models. Data from human studies are not yet conclusive, but initial results are promising.

Consumed in moderate amounts – especially from grass-fed milk – butter can be a valuable component of a balanced diet.

Ghee

Ghee is a clarified form of butter from which the protein components and water have been removed. This makes it longer lasting and easier to heat. Similar to butter, ghee contains butyrate as well as vitamins A and K2. In Ayurvedic medicine, it is traditionally considered to promote digestion and strengthen tissue. Inflammation-modulating effects have also been discussed in Western studies.

Coconut oil 

Coconut oil is another traditional fat source, characterized primarily by medium-chain triglycerides (MCTs). These are preferentially metabolized in the liver, which can lead to rapid energy supply. Studies have shown that MCTs have beneficial effects on satiety regulation and body weight under certain conditions. Antimicrobial properties are also being discussed.

olive oil

Extra virgin olive oil is a central component of the Mediterranean diet. In addition to its high content of monounsaturated fatty acids (especially oleic acid), it contains secondary plant compounds such as polyphenols, which can have antioxidant and anti-inflammatory effects.

Epidemiological studies have found an inverse association between olive oil consumption and the risk of cardiovascular disease, type 2 diabetes, and certain cancers. 

Beef fat (tallow)

Beef fat, traditionally known as tallow, has been a key frying and cooking fat for centuries. It contains predominantly saturated and monounsaturated fatty acids and is characterized by high oxidative stability at high temperatures—an advantage over polyunsaturated oils, which oxidize more quickly.

Unlike industrial vegetable oils, beef fat is minimally processed and contains no additives. Pasture-fed animals also contain physiologically relevant amounts of vitamin D , vitamin K2, and natural trans fats such as vaccenic acid , which behave metabolically differently than synthetic trans fats.

From a nutritional perspective, beef fat offers a heat-stable, nutrient-rich alternative to refined vegetable oils – especially in hot cooking. From a sustainability perspective, the use of tallow in the sense of nose-to-tail utilization is also increasingly viewed positively.

Highly processed seed oils: production, composition and health assessment

Commonly used industrial seed oils include soybean oil, corn oil, rapeseed oil, sunflower oil, and especially cottonseed oil. These oils are usually obtained through chemical extraction and refining. The production process often includes steps such as degumming, deacidification, deodorization, and heating, which can lead to the formation of oxidized lipid compounds. 

Particularly problematic are:

• a high content of polyunsaturated omega-6 fatty acids (especially linoleic acid), which can promote a pro-inflammatory environment when omega-3 intake is low,
• potentially harmful compounds such as trans fatty acids that can be formed during heat treatment,
• toxic residues such as gossypol in the case of inadequately refined cottonseed oil.

Epidemiological and animal studies indicate possible associations between the consumption of highly processed oils and metabolic dysfunctions such as insulin resistance, chronic low-grade inflammation, and obesity.

Recommendations from a nutritional perspective

• Fats with high oxidation stability, such as ghee, butter, coconut oil or beef fat, are suitable for heating during cooking.
• Olive oil should ideally be used cold to protect heat-labile polyphenols.
• A reduction in the ratio of omega-6 to omega-3 fatty acids can be achieved by increasing the consumption of fatty sea fish.
• Highly processed oils in ready-made products should play a minor role in the daily diet.

Conclusion

The blanket classification of fats as "good" or "bad" does not do justice to the current state of research. Rather, a differentiated approach is required that takes into account manufacturing processes, chemical stability, digestibility, and the context of overall consumption.

Traditional, minimally processed fat sources such as butter, ghee, coconut oil, beef fat, and olive oil are scientifically proven to be potentially beneficial to health when consumed as part of a varied diet. However, the critical examination of industrially processed seed oils remains relevant.