What are trans fats and how do they really harm you?

You've probably heard of "trans fats" before, usually in a whisper and in connection with fast food, chips, or pastries. But what exactly are they, and why are they such a big issue for your health?

Simply put: trans fats are unsaturated fatty acids whose chemical structure has been altered. This alteration makes them a real problem for our bodies. Most of them are created when liquid vegetable oils are industrially hydrogenated to make them spreadable and give them an extremely long shelf life.

What trans fats really are, explained simply

A selection of unhealthy foods such as donuts and French fries, which often contain trans fats.

Imagine the fats in your body as perfectly fitting building blocks. For everything to run smoothly, they must fit together perfectly. Healthy, unsaturated fats naturally have a slightly bent shape. This makes them flexible – ideal for flexible cell walls and a healthy metabolism.

Industrial trans fats are different. They have an unnatural, rigid, and straight structure. You could compare them to a bent key that simply no longer fits the lock. Instead of fulfilling their functions in the body, they block important processes and can lead to serious health problems in the long run.

Trans fats at a glance

Here is a quick overview summarizing the most important properties of trans fats:

feature	Description
Origin	Primarily through industrial hardening of vegetable oils
structure	Rigid, unnatural shape compared to healthy fats
Industrial benefits	Makes products durable, heat-stable and texture-optimized
Happen	In fried foods, baked goods, ready meals, margarine
Health	No benefit; increases the risk of cardiovascular disease

In short: They are convenient for industry, but problematic for your health.

Why the food industry (used to) love them

For food manufacturers, trans fats were a huge success for a long time. Through a process called partial hydrogenation, cheap vegetable oils were transformed into solid fats with unbeatable advantages:

Extreme shelf life: Cookies, crackers or ready meals stayed fresh and crisp for weeks.
Perfect consistency: They ensured the delicate texture in croissants or the creamy note in spreads.
High heat resistance: Ideal for deep-frying, as they can withstand high temperatures without becoming rancid.

These properties have made them a standard ingredient in countless processed foods. However, the health cost is high, because your body simply doesn't know what to do with these artificial fats.

The recommended upper limit is tiny.

Health organizations worldwide agree: Trans fats offer no health benefits whatsoever. On the contrary, they can significantly disrupt your fat metabolism .

The World Health Organization (WHO) recommends limiting the consumption of trans fats to less than 1% of daily energy intake .

With an average diet of 2000 calories per day, this equates to a tiny 2.2 grams . This amount is reached alarmingly quickly – often with just a single Berliner (doughnut) or a portion of deep-fried fries.

This knowledge is the first step to understanding why taking a close look at the ingredient list is so important. Only then can you make conscious choices for your health.

The difference between natural and industrial trans fats

A cow in a pasture, representing natural trans fats in milk and meat When we talk about "trans fats," many people lump everything together. But that's a mistake. To truly understand what's in your food, you need to know a crucial distinction: there are natural and artificially produced trans fats.

Your body reacts completely differently to each type. This knowledge is key to making the right choices for your health at the supermarket.

Nature actually produces trans fats itself, albeit only in small amounts. They are formed in the rumen of ruminants – cows, sheep, or goats – through perfectly normal bacterial processes. That's why you find natural trans fats in foods like butter, cheese, beef, and lamb.

According to current knowledge, these natural variants, in the usual small quantities, do not appear to have nearly the same harmful effects as their industrial counterparts.

The artificial danger from the factory

The real danger, which health experts have been warning about for years, lurks in industrially produced trans fats . These are the result of a chemical trick called "partial hydrogenation." In this process, liquid vegetable oils are treated with hydrogen under high pressure and heat to make them solid and spreadable.

This process unnaturally distorts the chemical structure of fatty acids. The result is the problematic trans fats, which your body can barely process.

The purpose of industrial hydrogenation was simple: to transform cheap vegetable oils into durable, texturizing fats for baked goods, frying fat, and ready-made meals. But your health is paying the price.

These fats used to be found almost everywhere. As recently as 2013, the average daily intake of trans fats in Germany was around 1.6 grams per day – a figure that came almost exclusively from industrially processed foods. You can find more information about the situation at that time in the fact sheet from the German Nutrition Society .

Why the difference is so important

The crucial point is therefore the origin and, above all, the quantity. While natural trans fats are considered harmless in moderation, the industrially produced versions are the real villains for your cardiovascular system.

Here are the key differences at a glance:

Origin: Naturally occurring in the rumen of ruminants vs. artificially through industrial hardening of vegetable oils.
Amount: Low concentration in meat and milk vs. often high concentration in highly processed foods.
Health effect: So far, no clearly negative effects have been proven for natural trans fats vs. demonstrably harmful to the heart and circulatory system for industrial trans fats.

It's not just about trans fats, though. A general imbalance between different types of fatty acids can be detrimental to your body. That's why it's wise not to focus on just one type of fat, but to consider the bigger picture. If you'd like to delve deeper into how important the right fats are for you, read our article on omega-3 fatty acids .

How trans fats endanger your heart health

Now things are getting serious. We know that industrial trans fats are problematic – but why exactly? Imagine your blood vessels as an ingenious system of pipes that supplies every single cell in your body with everything it needs. Industrial trans fats act like tiny saboteurs, causing disruption at two crucial points.

Their main target: your cholesterol levels. They disrupt the delicate balance between "bad" LDL cholesterol and "good" HDL cholesterol. And it is precisely this double negative effect that makes them a real threat to your cardiovascular system.

The double blow against your cholesterol

First of all, trans fats raise LDL cholesterol (low-density lipoprotein) . You might know it as the "bad" cholesterol, and for good reason. It tends to build up on the inner walls of your arteries. Over time, these deposits, also called plaques, can harden, narrowing the blood vessels and obstructing blood flow. This increases the risk of heart attacks and strokes.

At the same time, they do something else: they lower HDL cholesterol (high-density lipoprotein) . This is the "good" cholesterol, which has an important protective function. Think of it like a kind of garbage collection service for your arteries. It collects excess cholesterol and takes it to the liver, where it is broken down. If your HDL level drops, this important cleansing process no longer works properly.

This two-pronged attack – more harmful LDL and less protective HDL – is at the heart of the problem. If you'd like to delve deeper into how you can positively influence your cholesterol levels, take a look at our guide to lowering LDL cholesterol .

The following graphic clearly illustrates at a glance how much even small amounts of trans fats affect your blood lipid levels and the risk of disease.

Infographic showing how trans fats increase LDL cholesterol, lower HDL cholesterol and increase the risk of heart disease.

The data speak for themselves: Even low consumption of trans fats significantly worsens blood lipid levels and significantly increases the risk of heart disease.

Where trans fats hide in the supermarket

A person looks at the ingredient list of a product in the supermarket to identify trans fats.

So, now you know how insidious industrial trans fats can be for your heart. But where exactly are they lurking? The next step takes us straight to the supermarket – because that's precisely where these unhealthy fats are true masters of disguise.

They often hide in products where you'd least expect them. Consider this section your personal shopping compass. It will help you recognize the traps and confidently navigate around them.

The typical suspects on the shelf

Some supermarket aisles are veritable minefields for trans fats. This is simply because hydrogenated fats give many products precisely the properties that make them so popular: a long shelf life, a crispy texture, or a wonderfully creamy consistency.

Be especially vigilant with these product groups:

Baked goods & sweets: Industrially produced donuts, croissants, cookies, or puff pastry are the classics. Many cake glazes and creamy fillings also often contain hydrogenated fats to maintain their stability.
Ready meals & frozen foods: From frozen pizza to breaded fish fingers to quick ready-made soups – wherever long shelf life and ease of preparation are desired, trans fats can be hidden.
Fried foods & snacks: Frozen French fries, many potato chips, and even microwave popcorn are often fried or prepared in partially hydrogenated fats. The reason: These fats are extremely heat-stable and inexpensive.
Margarines & spreads: Although much has changed in this area, some inexpensive margarines or special baking fats still contain hydrogenated vegetable fats as a base.

Although initiatives to reduce trans fats have existed since 2012, Germany still lacks its own national law with clear limits. However, since April 2021, an EU-wide regulation has been in effect that limits the content to a maximum of 2 grams of industrial trans fats per 100 grams of fat in the product. You can find more information about the legal situation regarding trans fatty acids here.

Your most important tool: The ingredient list

Since manufacturers in the EU are not required to explicitly list trans fats in the nutrition information, the ingredient list on the back of the packaging becomes your best friend. This is where you can uncover the hidden fats.

Look out for terms like "hydrogenated vegetable fat" or "partially hydrogenated vegetable fat" . These phrases are the surest indication that industrial trans fats are involved.

A simple rule of thumb helps: the earlier an ingredient appears in the list, the higher its proportion in the product. And generally speaking, the shorter and more understandable the ingredient list, the better.

Find and enjoy clever alternatives

The best protection, of course, is to eat fresh, unprocessed foods as often as possible and cook for yourself. But we all know that sometimes things need to be quick. For those moments, the following overview will help you make better decisions at a glance.

Typical foods with a high trans fat potential

A comparison of risky products and healthier alternatives.

Product category	High-risk examples	Better alternatives
baked goods	Industrial croissants, donuts, puff pastry	Wholemeal bread, homemade cake with rapeseed oil, oat cookies
Snacks	Potato chips, crackers, microwave popcorn	Nuts, vegetable sticks with hummus, rice cakes
Spreadable fats	Inexpensive margarine, shortening	Butter in moderation, avocado, nut butter, high-quality plant-based spreads
Ready meals	Frozen pizza, breaded products, ready-made soups	Home-cooked meals, fresh salads, natural yogurt

By replacing these risky products with smart alternatives, you're not just doing your heart a huge favor. You'll feel fitter, more energetic, and simply better overall.

Practical tips for a low-trans-fat diet

Theory is all well and good, but real change happens in your kitchen. Avoiding trans fats might sound like rocket science, but with a few clever tricks, it's really not. It's not about giving up everything, but simply about making more conscious and better choices for your body.

The most effective way to regain control is actually quite simple: cook for yourself . When you work with fresh, unprocessed ingredients, you know exactly what ends up on your plate. This way, you avoid hidden trans fats from the start and give your body what it really needs – valuable nutrients instead of problematic industrial substances.

Choosing the right fats for your kitchen

Choosing the right oil is crucial. Not every fat is suitable for every temperature, and unstable oils can oxidize when heated, forming unhealthy compounds.

Here are a few simple recommendations for everyday life:

For frying over medium heat: Extra virgin olive oil or rapeseed oil are excellent choices. Both are relatively heat-stable and also provide valuable unsaturated fatty acids.
For salads and cold dishes: Cold-pressed oils such as linseed oil, walnut oil, or hemp oil are the stars here. They are full of delicate omega-3 fatty acids and should therefore never be heated.
For searing or deep-frying: When things need to get really hot in the pan, it's best to use special high-heat cooking oils (e.g., rapeseed oil) or clarified butter, also called ghee.

By using the right fats for the right purpose, you not only minimize the risk of accidentally producing trans fats, but also actively improve your health. A balanced diet is, after all, one of the most important building blocks for a long and healthy life. You can find out more in our article on longevity nutrition .

Smart snacks instead of ready-made products

We all know the feeling: that little hunger pang between meals is often the biggest trap. Instead of reaching for cookies, crackers, or other ready-made snacks, which are often full of hydrogenated fats, you can conjure up delicious and nutritious alternatives with very little effort.

A smart snack not only satisfies your hunger but also provides your body with energy and nutrients. It's a conscious decision for your well-being, not a last resort.

Why not try these ideas for home or on the go:

A handful of unsalted nuts such as almonds or pistachios.
Vegetable sticks (carrots, cucumbers, peppers) with a delicious hummus dip.
An apple with some nut butter.
Natural yogurt with fresh berries and a few rolled oats.

These small habits make a huge difference in the long run. You not only avoid trans fats, but also reduce sugar and unnecessary additives. This way, you actively take responsibility for your health – bite by bite.

Still have questions about trans fats? Here are the answers.

We've learned a lot about trans fats now – what they are, where they lurk, and how to avoid them. But experience shows that a few specific questions often remain. Let's clear them up now so you can feel truly confident when dealing with fats.

Are the natural trans fats from dairy products also a problem?

There's no need to worry. According to current knowledge, the natural trans fats that occur in small amounts in milk, cheese, or beef do not appear to have the same harmful effects as the industrially produced versions.

This is due, firstly, to their much lower concentration, and secondly, to their slightly different chemical structure. Official health recommendations therefore clearly target artificially produced trans fats. A yogurt or a piece of cheese is therefore absolutely no cause for concern.

How can I identify trans fats if they are not specifically listed?

This is actually the trickiest part, because in the EU, trans fats don't have to be listed separately in the nutrition information. Your most important tool is and remains the ingredient list on the back.

Be sure to keep an eye out for these two telltale phrases:

"hydrogenated vegetable fat"
"vegetable fat, partially hydrogenated"

If you come across any of these terms, it's a clear warning sign. As a rule of thumb: the longer and more complicated the ingredient list of a highly processed product, the more likely it is to contain unhealthy fats.

The easiest way to avoid trans fats? Opt for fresh, unprocessed foods. This way, you retain full control over what ends up on your plate.

Can trans fats also be produced when frying at home?

Theoretically, yes, but it strongly depends on the context. If you heat certain vegetable oils to very high temperatures and, above all, repeatedly – as happens when frying in a deep fryer – tiny amounts of trans fats can indeed be formed.

For normal pan-frying, these quantities are so minimal that they are not comparable to industrial processes . To be absolutely safe: Use heat-stable fats such as rapeseed oil or special frying oil and make sure not to heat the oil so much that it starts to smoke.

Are there any trans fats that are still considered safe?

The answer from health organizations like the WHO is unequivocal: No. Industrial trans fats have no health benefits whatsoever , and therefore there is no safe limit.

The recommendation is to reduce intake to as close to zero as possible. Your body simply doesn't need these artificial fats. So instead of obsessing over limits, it's much smarter and healthier to simply and consistently eliminate processed foods containing hydrogenated fats from your diet.

Your body is unique, and your metabolism has very individual needs. If you want to understand which fats and nutrients are best for you personally, the analyses from mybody-x.com can provide valuable insights. Discover with a DNA metabolism test how you can tailor your diet specifically to your genetic predisposition to effectively achieve your health goals.

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