ParkZeit interview: Do all fats do us harm?

No need to fear oils and butter

Although our bodies need them, fats have a bad reputation. In our interview, Dr Irene Brunhuber, consultant internist at Park Igls, sheds light on fats and their positive aspects, and offers advice on their uses. It’s time to take stock of fats, both good and bad.

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Dr Irene Brunhuber: People worry about fats because they see a link with obesity. Older people, especially, believe that eating fat will make them fat. This misconception is still deeply rooted, and saying otherwise tends to elicit scepticism.

From a purely mathematical point of view, it’s not a wrong assumption. A gram of fat provides 9.3kcal – around double the calorific content of a gram of carbohydrates or protein. Nevertheless, sugar and other fast-absorbing carbs like white flour products and fructose have a more significant impact on weight gain. Indeed, younger people tend to have a more nuanced perspective on fat.

The media have illuminated the topic from all angles, hyping up fashionable diets, not all of which are sound. Although this has had the effect of laying old misconceptions to rest, it has also created new myths. While the younger generation has learned that fats are not all bad, as we need them for energy and other physical processes, most people still feel unsure about them.

Brunhuber: The main protagonists in the digestion of fats are the acids in bile, which the liver produces, and digestive enzymes, which are released by the pancreas. Bile emulsifies dietary fat into tiny droplets which greatly increases the surface area of fat, making it available for breakdown by the digestive enzymes and easier to absorb in the small intestine. However, since fat is not water soluble, it is then transported to the bloodstream in the form of proteins (lipoproteins) from where it supplies the organs, including the liver.


Brunhuber: Weight, body mass index (BMI) and waist circumference can tell us a great deal, but none are entirely reliable and should only be used for preliminary assessments. Some scales available on the market offer a body fat measuring function, mostly through the soles of the feet. However, only the lower extremities can be measured through the soles, so the measurement on the scale is not a conclusive answer.

The bioimpedance measurements carried out at Park Igls are more informative, and more helpful during a course of treatment. Put simply, muscle mass and fat are measured by sending a weak and unnoticeable flow of alternating current through the body. This measures resistance and then produces a table of the data to provide information on your body’s fat, muscle mass and water content.

Body fat measurements above 30% in women and above 20% in men are considered obese. Body fat percentages between 15 and 20% are classed as average, while only extreme athletes or severely ill patients exhibit body fat values below 10%. These measurements always require evaluation by a trained medical professional. Furthermore, they are age-dependent. This is because fat reserves can be a good thing as we age, as they help us cope better with chronic diseases. However, we don’t always need to use all this technology: a simple look in the mirror can often tell us everything we need to know. For example, a large belly indicates that we have too much belly fat.

Brunhuber: High levels of body fat tend to go hand in hand with reduced self-esteem, as there is a mismatch between physical appearance and social pressures. Excess weight also makes movement difficult, adding pressure on the joints and hindering exercise. People who make repeated attempts to lose weight can also experience stigma and frustration. This dampens motivation and leads to reactive depression. On the other hand, a lack of adipose tissue, when body fat percentage falls below a certain level, is also undesirable as it causes a raft of different problems, including hormonal issues that can affect a woman’s periods.

Brunhuber: Low muscle mass can make it difficult to recognise excessive adipose tissue because a person’s weight can still be within healthy parameters.


Brunhuber: Not all fats are equal. Fatty acid saturation is important, with unsaturated being preferable to saturated. It’s easy to get these terms mixed up because their meaning suggests the opposite when used in everyday life. We distinguish between animal fats with a low unsaturated fatty acid content and vegetable fats that contain a high percentage of unsaturated fatty acids. These are contained in cold-pressed oils (olive oil, linseed oil, rapeseed oil, etc.), seeds (linseed, pumpkin seeds, etc.), nuts and fish (salmon, herring, mackerel, etc.). Polyunsaturated omega-3 fatty acids are highly beneficial and only occur in fish and plants: the body cannot produce them on its own. You should also be careful with hardened vegetable fats. These are in things like puff pastry, ready-made soups and cakes, and contain very low levels of unsaturated fatty acids.

Brunhuber: Nutritionists recommend that healthy people with no underlying health issues can cover 30% of their daily energy intake with fat; that’s around 60g to 70g per day. Many diets with a higher fat percentage are perfectly healthy, but it’s the quality of the fat that counts, not just the quantity. Some people actually need more fat, but these have to be good fats. The percentage of saturated fats (animal fats) should be less than 10% of total energy intake. Sticking to the daily recommendations can be difficult since fat is a major flavour carrier. This is especially true if you don’t cook for yourself because you won’t generally know what fats have been used. The only way around this situation is to cook your own meals and take home-prepared food to work.

Of course, better labelling would be great, and I’d like to see a clear traffic light system. The barely legible information on packaging can be difficult for people to read.

Brunhuber: Because visceral fat has an inflammatory effect, a diet heavily laden with animal fats will sooner or later lead to an increase in inflammation. It also means that fewer of the anti-inflammatory fats such as omega-3 and 9 are absorbed with food, provoking an inevitable vicious cycle: inflammation causes pain → which reduces mobility → which leads to weight gain → and additional health complaints → chronic illness increases psychological stress → people then lack motivation to change their lifestyle → and search for comfort in chocolate/food/alcohol.

A diet heavy in fat also increases the risk of arteriosclerosis, more popularly known as hardening of the arteries. This is where cholesterol and other fat deposits lead to the narrowing of major blood vessels such as the carotid artery, coronary vessels, and leg arteries. As a result, the body’s organs receive insufficient oxygen, thereby increasing the risk of organ damage. In Austria, 30,000 to 40,000 deaths a year are attributable to heart attacks and strokes resulting from arteriosclerosis, and around 20% of the population are classed as at risk.

When excessive weight gain, high blood pressure, increased blood sugar levels and an abnormal fat metabolism all appear at the same time, the medical world classes this as metabolic syndrome. In other words, when individual risk factors interact, the risk is not aggregated but exponentiated.

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Brunhuber: Cholesterol isn’t bad in itself. It’s the precursor to many hormones and, as well as being a major component of cell membranes, it is necessary for the production of bile acid. Food only supplies some of the body’s cholesterol, the rest is produced by the body itself. However, external influence is only possible to a limited extent.

Brunhuber: Blood tests to measure the cholesterol level differentiate between total, LDL and HDL cholesterol, and triglycerides. Risk factors and pre-existing conditions must be taken into account to establish the target level. For instance, healthy people with no risk factors should have an LDL level below 115mg/dl, although higher levels are also tolerable, and an HDL level over 45mg/dl. Someone with coronary heart disease or a circulatory system disease should expect to have an LDL level below 70mg/dl. Of course, these values should also be viewed with caution since everyone is different.

Brunhuber: Yes, we can. Although HDL cholesterol and, to a lesser extent, LDL cholesterol have a genetic basis, levels can certainly be improved by diet. Phytosterols, chemical compounds found in plants, are structurally similar to cholesterol in animal products, and can lower the cholesterol content in blood plasma by up to 10%, thereby reducing the risk of disease. Virgin oils, healthy fats and seeds – good fats – contain large quantities of phytosterols. Furthermore, dietary fibres found in fruit, vegetables, wholemeal products, ground linseed and psyllium bind fats, and can reduce LDL cholesterol by 5%.

All in all, success can be achieved by opting for the right foods. On the other hand, quick-fix diets don’t accomplish anything. To reduce the incidence of illnesses caused by fat metabolism issues, we have to make long-term changes to our diet. Not everything needs to be banished from our menus, but 80% of our daily intake should be good for us. It’s easy if you can stick to preparing food from scratch. Making your own wholemeal sandwich with cream cheese and salad beats a sausage bap by a mile. Fruit and a few nuts are great for both body and mind, while sausage baps, etc. can only be of detriment to the body and lower your energy levels.


Brunhuber: Three factors affect fat burning:

Exercise: People who don’t exercise much burn less fat. Endurance and weight training boost fat burning.

A diet high in sugar (including fast-absorbing carbohydrates): This kind of diet leads to increased insulin levels that block fat burning. Energy bars and drinks following exercise are counterproductive. Note: even alcohol stops the burning of fat!

Stress: Stress can lead to chronically elevated cortisol levels. As well as slowing the breakdown of fats, this reduces muscle mass.

Brunhuber: The guidelines regarding surgery are clear, and an operation would be considered for someone with class 3 obesity, i.e. a BMI above 40. Although surgery would also be an option for people with class 2 obesity (BMI 35-40) and associated health problems, we would start with conservative treatment: we’d look at improving their diet, provide advice on lifestyle changes, and work with the patient to identify a suitable form of exercise therapy. Also, but rarely, there are cases when we would prescribe medication as a therapeutic intervention for adults.

To sum up, I would say that the best way to combat the fear of fat is with information. Knowing about fats and their effects can even help people take their health into their own hands. Unless people examine their own eating habits and change their behaviours, they are unlikely to achieve lasting success. And change can be delicious! If you like the Mediterranean diet of vegetables, fish, and olive oil, changing your diet won’t be a problem.

Gesundheitszentrum Park Igls in Tirol

Dr Irene Brunhuber – Consultant internist and Mayr Physician at the Park Igls Mayr clinic