Healthy Fats & Oils: Which Fats Are Really Healthy

For a long time, fat was considered the main cause of overweight, cardiovascular diseases, and metabolic problems. "Low fat" was the guiding principle of many dietary recommendations for decades. However, modern nutritional science now paints a much more nuanced picture: it is not the fat itself that is the problem—rather, the type of fat. Certain fats and oils are even essential for your health and can have preventive as well as therapeutic effects.

But which fats are truly healthy? And what does the science say about it?

Fat is not just fat – a brief overview

Chemically speaking, fats are composed of fatty acids, which can be roughly divided into three groups:

• Saturated fatty acids

• Monounsaturated fatty acids

• Polyunsaturated fatty acids

Additionally, there are trans fatty acids, which are now considered particularly harmful to health.

The health effects of fats largely depend on this structure—and how heavily they have been industrially processed.

What distinguishes fats chemically

Fats consist of so-called fatty acids. These, in turn, are long chains of carbon and hydrogen atoms. What is crucial is how these atoms are connected to each other. If all bonds are "single," it is referred to as saturated fatty acids, and if they contain one or more so-called double bonds, they are called unsaturated fatty acids.

These double bonds change the behavior of fatty acids in the body significantly. They make fats more mobile, more reactive, and biologically active. This is exactly where the key to their health potential lies.

Unsaturated fatty acids

Mono- and polyunsaturated fatty acids are now considered particularly health-promoting. Their chemical structure ensures that cell membranes remain flexible, inflammatory processes are regulated, and fat metabolism is positively influenced.

A classic example is olive oil, which is rich in monounsaturated fatty acids. Studies on the Mediterranean diet have shown for years that people who regularly use olive oil are less likely to suffer from cardiovascular diseases. Chemically, these fatty acids primarily lower LDL cholesterol, which can deposit in the walls of blood vessels, while the protective HDL cholesterol is maintained. Additionally, high-quality olive oil contains phytochemicals that reduce oxidative stress and silent inflammation.

Even stronger wirken omega-3 fatty acids, a special group of polyunsaturated fatty acids. They are found, among other things, in fatty sea fish, linseed oil, and walnuts. Due to their multiple double bonds, they serve in the body as precursors for hormone-like substances that slow down inflammation, regulate blood clotting, and improve vascular function. Large clinical studies show that adequate omega-3 intake is associated with a lower risk of heart attack, stroke, and inflammatory diseases. These fats are also essential for the brain and nervous system, as they form an essential component of nerve cell membranes.

Omega-6 fatty acids – necessary, but often out of balance

In addition to omega-3, there are omega-6 fatty acids, which are also polyunsaturated and essential. Chemically, they are very similar to omega-3 fatty acids, but in metabolism, they can act partially in opposition. While omega-3 tends to have an anti-inflammatory effect, omega-6 fatty acids can support inflammatory processes – what is useful in certain situations, such as in immune defense.

It becomes problematic when the relationship is out of balance. In the Western diet, omega-6-rich oils like sunflower or corn oil predominate, while omega-3 sources are often lacking. Studies show that omega-6 itself is not harmful, but that discrepancy, which can promote chronic inflammations in the long term.

Saturated fatty acids - particularly stable

Saturated fatty acids are chemically particularly stable fatty acids without double bonds, which are primarily found in butter, cheese, cream, meat, as well as in coconut and palm fat. In the body, they mainly influence cholesterol metabolism: studies show that they can increase LDL cholesterol levels, which is considered a risk factor for arteriosclerosis. Interestingly, the effect is not as simple as long thought. More recent research, including the comprehensive overview¹ by Astrup et al. (JACC 2020), shows that the relationship between saturated fatty acids and cardiovascular diseases is complex. While LDL cholesterol does increase, not all LDL particles contribute equally to the risk, and epidemiological studies do not find a consistent increase in heart attack risk solely from saturated fats.

These results shed new light on the role of saturated fats: They are not automatically harmful to health, but under certain conditions, they can alter the lipid profile in the blood. Their effect depends on numerous factors, including the type of food in which they are contained and the interaction with other nutrients.

Saturated fats provide energy, are components of cell membranes, and fulfill metabolic functions. Since the body can produce them itself, they do not necessarily need to be consumed through diet. Experts therefore recommend: In a health-promoting diet, they should not constitute the main proportion of fat intake, but should be supplemented or partially replaced by unsaturated fatty acids.

Trans fats - chemically altered, biologically problematic

A special role is played by trans fatty acids. They are formed when vegetable oils are industrially hardened or highly heated. Chemically, they are unsaturated fatty acids, but their structure has been artificially altered. This change causes them to behave in the body similarly to saturated fats, but they promote Inflammatory processes.

The study situation is clear here: trans fats significantly increase the risk of cardiovascular diseases, diabetes, and chronic inflammations. From a health perspective, they should preferably avoided.

Fat as a Health Factor - Not as an Opponent

Fat fulfills vital functions in the human body. It is a component of every cell membrane, necessary for the production of hormones, and essential for the absorption of fat-soluble vitamins. Current research shows that a higher-fat diet can indeed be healthy – if the quality of the fats is right.

Those who rely on natural, unsaturated fats, regularly incorporate omega-3 sources, and avoid highly processed fat products use fat not as a risk factor, but as a protective factor for health.