Healthy Fats vs. Unhealthy Fats: What Should You Look Out For?

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While some fats are essential for optimal health, others can harm the body.

May 13, 2024

Jana Ackermann

  • Food
  • Health

Healthy Fats vs. Unhealthy Fats: What Should You Look Out For?

Fats, even though they have a bad reputation, are essential in our diet. A look at the major differences

Fats play an important role in our body. Along with carbohydrates and protein, they are among the three main nutrients, each of which is very important for our health and our well-being . "Fats are energy stores and vital for our brain, our nerves, and every single cell," explains Dr. Sophie Neuhaus, specialist in anesthesiology at the University Hospital Heidelberg.

However, fat is not just fat: While some fats are essential for optimal health, others can be harmful if consumed in large quantities. A distinction is made between high-quality saturated, monounsaturated, and polyunsaturated fatty acids, as well as the harmful trans fats. The latter belong to the group of unsaturated fatty acids, but have no positive effect on the body.

These foods contain healthy fats

The body can produce certain omega-3 and omega-6 fatty acids itself, but not all of them. Two of them - called essential fatty acids - must be obtained through diet. "Only with the help of fats can our body, among other things, absorb the fat-soluble vitamins A, D, E, and K," says Dr. Neuhaus.

As a rule of thumb: The more plant-based and fresh foods we eat, the better we are supplied with healthy unsaturated fatty acids. These include Foods such as fatty fish (salmon, herring, mackerel, trout, and sardines), vegetable oils, nuts, nut butter, seeds like chia or flaxseeds, and avocados.

The fats found in them contain monounsaturated and polyunsaturated fatty acids, which have been proven to protect the cardiovascular system by lowering cholesterol levels and reducing inflammation in the body.

The power of high-quality oils

An indispensable kitchen staple is high-quality organic olive oil. It consists largely of unsaturated fatty acids and contains valuable vitamin E, secondary plant compounds, and protects the heart the most. But walnut, peanut, linseed, rapeseed, and safflower oils also contain plenty of healthy fats and complement a balanced diet.

“Regarding the quality of vegetable oils, it is important to look for a native cold-pressed production and organic raw materials,” recommends the doctor. This way, the natural nutrients and a high proportion of healthy fatty acids in the cooking oils are preserved.

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The German Nutrition Society (DGE) recommends one to two servings of fatty fish such as salmon or mackerel per week.

Omega-3 and Omega-6 fatty acids are so important

When it comes to essential fatty acids, you can't avoid omega-3 and omega-6 fatty acids. Our body needs both for health, such as for the cardiovascular system, hormone regulation, eyes, and brain. Omega-3 fatty acids have anti-inflammatory properties and can help reduce inflammation in the body, while omega-6 is important for regulating our energy production, bones, and the health of our skin and hair.

For omega-3 and omega-6 to work in our bodies, the right balance is crucial: “The ratio of omega-6 to omega-3 should be between 1:1 and 5:1,” advises Dr. Neuhaus. Studies show that in many western countries, the average intake of omega-3 fatty acids is significantly below recommended levels.

Therefore, the German Society for Nutrition (DGE) recommends one to two servings of fatty fish like salmon or mackerel per week—they contain some particularly valuable omega-3 fatty acids. For those on a plant-based diet, Dr. Neuhaus suggests incorporating linseed oil into daily nutrition, as the primary plant-based source for the ideal omega-3 ratio.

For example, one tablespoon of linseed oil can be stirred into yogurt in the morning, used in dressings, or added to smoothies; this way, fat-soluble vitamins can be better absorbed through the intestines into the body. It is important to store linseed oil in a dark and cool place and to use it up within about three weeks after opening.

"Otherwise it can oxidize, leading to an unpleasant taste and a loss of its nutritional benefits." More omega-3 fatty acids can also be found in green leafy vegetables, herbs, kale, cress, and dandelion.

That's why saturated fatty acids are also important for us

Saturated fatty acids are mainly found in animal products such as butter, milk, cream, cheese, sausage, bacon, meat, and lard, as well as in plant fats like coconut oil, palm oil, palm fat, and cocoa butter. The saturated fatty acids they contain have a bad reputation, but according to Dr. Neuhaus, there are now several studies that question this. Saturated fatty acids give us energy and protect our organs, yet according to the DGE, intake should be limited to 7 to 10 percent of total energy consumption.

Interesting is: Studies have shown that the healthy benefits of nutrients increase when we choose products of high organic quality. Milk and raw milk butter from organic farming, for example, also contain unsaturated fatty acids – and thus have a completely different health value than processed foods.

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Fat contains more calories per gram than carbohydrates and proteins.

Harmful trans fats? No thanks!

This brings us to the fats that bring no benefit to the body and can even be harmful: the so-called trans fatty acids. They arise through the process of highly processed food production, where oils are heavily heated or once liquid oils are artificially hardened to be processed, for instance, into spreadable margarine.

Trans fats can be found in almost all fatty ready meals like pizza, frozen dishes, or baking mixes, as well as in margarine, chips, cookies, donuts, industrial pastries, nut-nougat creams, and fried fast food. In very small quantities, they can also be found in meat, fish, and milk.

The author Bas Kast writes in his guidebook “The Nutrition Compass”: “Trans fats fuel the inflammatory processes in the body and lead to insulin resistance. They are toxic and should be avoided at all costs.” Dr. Neuhaus adds: “Studies have shown that trans fats increase the concentration of LDL cholesterol in the blood, which is ultimately a major risk factor for the development of coronary heart disease.” The more trans fatty acids we consume, the higher the risk.

But even in our own kitchen, we should be careful when frying and baking with oils: trans fats are formed at 130 degrees Celsius. The benefits of unsaturated fatty acids are lost, while trans fats can lead to health problems. When heating oils and fats, it is important to choose those with a high smoke point that are stable enough to withstand the high temperatures of cooking.

For frying at a light to medium temperature, butter or ghee is suitable, while coconut oil or refined vegetable oils like sunflower oil, peanut oil, or rapeseed oil are suitable for medium to higher temperatures.

Does fat make you fat?

Many prejudices about fat still persist. One of the biggest: fat makes you fat. But is that really true? Not really: weight gain depends on the overall balance between the calories consumed and the energy expenditure (metabolism and physical activity). If we consume more calories than the body burns, we gain weight - regardless of whether these calories come from fats, carbohydrates, or proteins.

However, fat contains more calories per gram than carbohydrates and proteins, so excessive consumption of fatty foods can easily lead to excessive calorie intake - and in the long term to weight gain if the energy is not burned through exercise. So it's, as with everything, about balance.

“Low-fat” products are trendy - but are they really healthier?

As part of the "diet culture," low-fat products are very popular, and supermarkets are full of low-fat yogurts, light dressings, light chips, or diet cereal bars. For a long time, it was said that low-fat foods contribute to a healthier diet and should help with weight loss: triggered in the 1970s when scientific studies began to establish a link between a high-fat diet and cardiovascular diseases as well as overweight.

Meanwhile, it is known: Fat is the most energy-rich macronutrient. It provides about nine calories per gram, compared to about four calories per gram for both carbohydrates and protein.

The result of consuming light products can be that we do not feel full and instead eat more fast carbohydrates like pasta, white bread, or sugared industrial products, which turn out to be far unhealthier. "Therefore, one should not banish good fats from their diet," advises the expert.

The DGE recommends consuming no more than 30 percent of daily energy in the form of fat per day. With a daily energy requirement of 2000 to 2500 kcal, this corresponds to about 60 to 80 g of fat. For illustration: "In one tablespoon of oil or one tablespoon of butter, there are about 10 grams of fat. By using 3 tablespoons of high-quality oil and 1 tablespoon of butter, about 20 to 40 g remain for non-visible fats from other foods."

Thus, many natural high-fat foods - like olive oil, linseed oil, nuts, seeds, or avocados - are simply healthy and should regularly be on our plates, while we should preferably avoid trans fats. Ultimately, a balanced diet with a variety of unprocessed and organic foods is the key to a healthy lifestyle, regardless of whether they are low in fat or not.