Nutrition

Your ultimate guide to dietary fats

Finally, I get to write about fats. You might wonder how come that I am happy about it. To me, for a very long time this topic was a mess. There was so much isolated information about fats out there. “Fats are bad. Yes, but some fats are not bad. Okay. Too much fat is related with heart disease. But some fasts are good for the heart as well? What is omega 3 and omega 6 and who is the bad guy and who is the good guy? And what the hell is all the fuzz about cholesterol?“.

I think not only I get confused by all those claims that seem to be both good and bad, and sometimes the exact opposite. When I finally got the big picture about fats, many things out of the sudden made so much more sense. It now is way easier to understand which food is a good pick and which is not.

That’s why I want to dedicate this article about our nutritional fats exclusively. There are tons of related topics to talk about – like obesity, disease and problems in our food industry. Here however, I want to focus on the understanding of fats and knowing how to choose the right foods fat-wise.

Fat and triglyceride

Fat is in general the most energy dense macro nutrient in our diet and comes with 9 kcal of energy per gram. Besides as a source of energy, all fats have several functions in our body, as to be part of hormones, tissue or in our brain. Due to its high density, fat is also the way of storing energy “long term” in our body.

When transported or stored, fat usually comes in the form of triglyceride. That’s mainly a glyceride molecule, being capable of holding three individual fatty acids. We find fat in this form as well in our food, in both animal products and oily fats from plants.

Triglycerides are an important key figure in our blood. High levels can indicate obesity and are associated with atherosclerosis, cardiovascular disease and more, even at the absence of high cholesterol levels. You therefore want your total blood triglyceride concentration to be below 150 mg / dl.

The WHO recommends that the overall intake of dietary fats is less than 30% of your daily caloric needs.

Saturated and unsaturated?

Each fatty acid is categorized in either saturated, mono-unsaturated and poly-unsaturated fats. To understand why and how you can easily detect them in food, a look at their chemical structure can be helpful.

A fatty acid mainly consists of an acid group and a long carbon hydrogen chain. Each Carbon atom is capable of binding to 4 other atoms due to its free electrons. This allows the carbon to build a chain, by linking to another carbon on two opposite electrons. The other two electrons can be filled with hydrogen or can be used to build a double bond to one of its neighbouring carbon atoms, provided the neighbour has a free electron available too.

If all connections are single bonds between the carbon atoms, the other two available electrons are carrying a hydrogen atom. The fat therefore is called saturated. In its structure a saturated fat is like a long, slightly zigzagged stick.

When at one of the carbon bonds two hydrogen are missing, the carbon atoms can build a double bond. The fat now is called unsaturated. In a natural unsaturated fat, the hydrogen atoms sit on the same side of the bond, so that the connection builds an angle instead of a more or less straight connection. In this case, we talk about a cis configuration or a cis bond. When the hydrogen sits on the opposite of this bond, we look at a trans fat, which – spoiler alert – is the worst type of fat you can encounter.

The good, the bad and the ugly.

Depending on the amount of double bonds, you can distinguish between mono and poly unsaturated fats. Within the poly unsaturated fats we find two groups of essential and semi essential fats, the omega 3 and 6 fatty acids. They are called like that, because the number indicates in which position of the chain they have their first double bond. For those fatty acids we have a minimum in our diet to fulfil. All the rest of the fats is less relevant and their intake usually should be kept low.

Saturated fats

Yep! That’s the bad guy. Even though saturated fats do have a purpose besides energy, they are associated with many diseases and negative health impacts. In general, you want to avoid them in your diet. After all, they are not essential and can be synthesized when needed. You can spot high amounts of saturated fats, if the oil or fat itself is solid at room temperature.

Coconut oil. Definitely high in saturated fats, definitely something you want to eat in moderate portions.

Saturated fats raise your levels of Cholesterol, especially LDL Cholesterol. It is recommended to not cover more than 10% of your energy through saturated fats.

Mono-unsaturated fats

Mono unsaturated fats belong to the good guys. Just like saturated fats, they also can be synthesized by the body when needed. They get used as building blocks for membranes, hormones and more. Even though they are not essential in our diet, avoiding them can lead to dry skin, broken nails and more, as they reduce the oxidative stress and help us to stay fresh and young longer.

Unlike saturated fat, unsaturated fats tend to lower your cholesterol levels and therefore lower your overall risk of heart disease. Keep in mind, that it is still recommended to not excess fat overall. If your levels of triglycerides raise, the viscosity of your blood raises as well, which then again can lead to circulation problems.

To put things practical: what you want to do, is replacing saturated fats with unsaturated fats as much as possible, while making sure to not provide more than 30% of your daily energy from fat. Just adding more oil on top to get the proportional contribution of saturated fat down is just not a good idea.

Omega 3 and 6 polyunsaturated fats

Omega 3 and 6 are two groups of the poly unsaturated fats, meaning fats with more than one double bond in the long carbon chain. One special thing they have in common is that they are processed by the same enzymes. They therefore compete in their processing, whereas a balance too high on the omega 6 side can cause negative side effects. Both of them are considered essential, meaning we cannot produce them and need to provide high enough amounts from food.

The omega 3 fatty acids are a sequence of 3 fatty acids, where the body is able to “upgrade” one acid to another. The chain starts with the alpha-linoleic acid ALA, which exclusively can be found in plant fats. It can be transformed to eicosapentaenoic acid EPA and then further on to DHA docosahexaenoic acid. EPA and DHA are associated with vessel widening, anti-inflammatory effects and good brain function. They furthermore can have preventive effects on kidney diseases, high blood pressure and more. They lower your overall and LDL cholesterol by promoting the production of the “good” HDL. You find both of them in omega 3 rich foods like seafood, fish and algae. A lack of omega 3 is associated with neurological issues like depression, Alzheimer and ADHS.

Omega 6 works kind of the same way. It starts with linoleic acid LA, which can only be found in plant fats as well, that can be transformed to arachidonic acid AA, which is exclusively found in animal products. Omega 6 is important for brain health, skin and hair growth.

The intake of omega 6 is often associated with lowering LDL cholesterol. However, science is not clear about it yet and it seems like the effect comes more from the reduction of saturated fats when swapping with omega 3 and 6, according to more recent studies.

The tricky part about Omega 3 and 6 is that they are synthesized by the same enzymes. Taking high amounts from the one can block the processing of the other. A too high intake of omega 6 therefore can reverse the positive effects from omega 3, by blocking out the chain of synthesis. A too high intake of omega 6 in proportion to omega 3 can have inflammatory effects as a result.

Both Omega 3 and 6 are synthesized by the same enzyme. Make sure to keep room for your omega 3 in your diet.

Since both omegas are considered essential, you must supply both fatty acids through dietary means. Completely cutting omega 6 is not a good idea. It is more important to have a good ratio between omega 3 an 6. The recommended proportion between omega 3 and 6 is 1:4 or lower. The more Omega 3 in relation to omega 6, the better. In our modern western diet however, the ratio often is between 1:15 and 1:20, depending on how you eat. With a proper junk food diet, you can skyrocket this even further.

Omega 3 and 6 on a vegan diet

When not eating any oily fish, you rely on the intake of ALA solely and are dependent on the synthesis of EPA and DHA fatty acids. When not consuming EPA and DHA directly, the conversion rate from ALA raises. However, it still may be a bottleneck. Considering that the synthesis can be blocked by high intake of LA, it is even more important to obtain a good amount of omega 3 in a good relation with omega 6. Providing good amounts of ALA therefore is more crucial.

If however DHA and EPA get supplemented through algae or fish oil, the conversion rate can drop 70-80%. So you should stick to either focusing on a sufficient natural supply of ALA, or stick to supplements. If you supplement “from time to time”, your risk in having a lower conversion rate overall, while not covering your need through the lack of DHA and EPA on most of the days.

Trans fatty acids

Technically, trans fatty acids are also unsaturated fats. Like the normal unsaturated fatty acid, trans fats contain one or more double bonds. In natural unsaturated fats the bond creates an angle, because the hydrogen atoms sit on the same side of the double bond. Through chemical processing or just plain heat, it can happen that the hydrogen swap their position and sit on the opposite of the double bond.

This might not sound like much, but it completely changes the dimensional structure of the molecule. Instead of having multiple folds in the chain, trans fatty acids now hold a small zigzag bond but continues in a straight line, as if it was saturated fat. So we have in the end something that has the same chemical sum as a normal unsaturated fat, but follows the form factor of a saturated fat. Trans fat is usually firm at room temperature, just like its saturated look-alike. They are also called hydrogenized oils.

As you can imagine, those fatty acids are not considered healthy. Even though their whole impact is not yet fully uncovered, they surely can impact your blood cholesterol levels negatively, by both raising LDL and lowering HDL concentrations. So you absolutely want to avoid them.

Trans fats were used much in spread fats like margarine, because they serve as a cheap alternative to saturated fats. Luckily, this trend has stopped and many governments have restricted the use of trans fats. Still, you can find them in sweet and oily baked goods. Here they are created “on the fly”, when baking oils at high temperatures over long time.

You can as well create them accidentally, by frying oils too hot and too long. Some oils, especially those strong in unsaturated fats, tend to break more easily than others. You therefore should look out on what you use for frying and how hot you fry oils overall.

Cholesterol

Cholesterol is a fat-like substance that our body needs. You mainly find it in cell membranes, but it is also needed to build hormones and vitamin D. Your liver is responsible for the cholesterol household, as it can synthesize all it needs. You also find cholesterol in all sorts of animal products, since it is part of animal cells.

Depending on where you look, you may find hard limits for dietary cholesterol of around 300 mg / day, other countries recommend keeping the intake as low as possible, without naming a fixed threshold. Your liver contributes to your total cholesterol by synthesizing around 800 mg of cholesterol on its own. The more you take in your diet, the less will be produced.

Most people have a good response on the cholesterol intake and adapt to higher amounts and the blood cholesterol levels respond more to the intake of high amounts of saturated fat and fat in general. If your overall blood cholesterol is already high, or have other metabolic conditions like diabetes, lowering your dietary cholesterol along with saturated fat is recommended.

Fat and fatty substances like cholesterol naturally won’t mix well with water or blood. Your liver releases cholesterol into the blood stream, by binding it to a so-called lipoprotein. This protein is the marker for your overall blood cholesterol. You can distinguish between a low density lipoprotein LDL and a high density protein called HDL.

In order to transport cholesterol from your liver towards its destination, LDL will be released. HDL on the other hand is responsible for the transport of used up cholesterol back to the liver, where it either gets resynthesized or kicked out.

Saturated fats are stimulating the production of cholesterol and the release of more LDL into your blood. Sadly, LDL can get stuck in your blood vessels and build up plaques. Having those plaques is called atherosclerosis. They are responsible for giving you heart attacks, strokes or stuck veins in your body.

You may have heard that you can call LDL the “bad” and HDL the “good” cholesterol. But recent science shows, that in the end LDL and overall cholesterol markers define your risk of atherosclerosis.

If your overall cholesterol counts higher than 200 mg / dl, this is an alarming signal and you should consult a doctor. The okay range is from 200 to 150 mg / dl. This cholesterol level itself is considered fine, unless you are having other risk factors involved. If you manage to keep your overall cholesterol levels below 150 and LDL below 75 mg / dl, the likeliness for developing CHD practically is stopped and can even reverse previously built up plagues.

Mid post summary

Fat is our most energy rich nutrient. It provides 9 kcal per gram. Fat, or fatty acids, mostly occur in triglycerides. That’s a glycerin molecule holding 3 fatty acids.

You can distinguish between saturated fats, mono unsaturated fats and poly unsaturated fats. While unsaturated fats are considered heart-healthy, too high amounts of saturated fat are linked to long term diseases and high cholesterol levels, especially of the “bad” cholesterol LDL. Your intake of saturated fats therefore should be limited.

There are two essential families of poly unsaturated fatty acids, the omega 3 and 6. Both groups are important for our health and should be supplied frequently. It is however important, to keep them in balance, because a too strong omega 6 to 3 ratio can boost your inflammation markers. You should try to hit an omega 6 to 3 ratio of 4:1 or better.

Plant foods usually provide only the “base” fat of a series, which can be transformed to other fats of the family. Those “upgraded” fats are exclusively found in animal products. Omega 6 is strong on foods from land animals, while omega 3 mostly can be found in fish and seafood.

The fourth and final group of fatty acids are so called trans-fats. You can imagine them as “broken” unsaturated fats, that look like their saturated correspondent. They are generally bad.

You can break down your fat consumption easily to four simple rules:

  • Your total fat should be 30% or lower
  • Your saturated fat intake should be 10% or lower
  • Provide at least 0,5% of your calories from omega 3, while not exceeding the fivefold supply of omega 6
  • Avoid trans fats wherever you can.

Fats on our plate

Now that we know how fat works and how we should handle it, we finally can take a look at our foods. Since anything contains fat in different compositions, finding the right path might feel overwhelming in the beginning. But let’s break it down one by one.

Since our fat limits and requirements are bound to our total caloric intake, we can look at fats again from another perspective. What counts in the end, is what you eat in a day. Any food providing more than 30% of calories from fat, should be outbalanced with foods that are below that threshold, to stay within a good area.

The same rule as for your overall fat intake applies to eating saturated fats. If you eat high amounts of saturated fats, you should consequently focus more on monounsaturated fats. If one fat source consists less than 30% of saturated fat in its total composition, it is a good pick to support a healthy balance

When looking at your omegas, you should care more about the ratio between omega 3 and omega 6 fatty acids than not getting to many of them. As long as you keep them in a good balance, it is hard to get too much of it, unless you overshoot your overall caloric intake from fat.

So what is a good approach to get your fat household running on a good balance?

Generally speaking, avoid eating high amounts of fats overall, and especially avoid high amounts of foods that have a bad fat composition. A good way of getting started here, is focusing on building a good base of healthy fats in one meal. If you eat a good bunch of a well composed fat source, you get a solid foundation for the day. Make sure you don’t ruin it by eating too many other fats with a bad profile on top of that, so that things stay balanced.

In practice that means to get a good fat source into your diet and make that one count on the balance. If your “base” is strong enough on omega 3 and mono unsaturated fats, you got some room for other foods that don’t follow the good composition and won’t break the overall picture by outweighing your healthy fats.

All referenced foods and their corresponding fat data of the following chapters have been taken from the platform cronometer.com. You can find the referred data in a tabular form in this spreadsheet.

Oils and spreadable fats

Oils are usually pure and bring 100% of their calories from fat. Besides fat there are usually no other components like water, unless it is an artificially crafted spread. One gram of oil or spreadable fat therefore is highly calorie dense. If you take one table spoon of oil or butter (around 13g) you already add between 100 and 115 calories to your plate. You should therefore only use little amounts of food, as you quickly can overshoot your energy needs with that. Generally: don’t drown your food in oil.

Animal fats like butter or lard usually come with a high amount of saturated fats and you usually find them in a solid form. But not only animal fats have a bad composition of saturated vs unsaturated fats. Especially tropical oils like coconut butter or palm oil have a very poor saturated to unsaturated fat ratio. You should not treat them as your main fat source and be very restrictive in their use.

When looking at the rest of the plant based oils, the saturated fats are usually on a good level and contribute less than one third of calories. There’s one thing you still should absolutely avoid, which are refined oils.

As you can see, most oils have an ok profile, except the tropical ones. You defenitely don’t want to miss out on that huge yellow bar on the left!

Diet margarine can have a very good fat profile. In the end it is designed around a healthy fat composition. It is however a highly processed food and it is worth checking the ingredients list.

Oils and frying

For frying you need to make sure to use a suitable oil. The more unsaturated – especially poly-unsaturated – fats oils contain, the less heat-resistant they are. If you want to fry, it is usually a safe pick to go for oils with a high stability. You can go for saturated fats in general, or you pick a good heat-resistant oil.

Coconut oil or animal fats are generally safer in frying, but they come with high amounts on saturated fats. So that’s not a nice profile. Sunflower oil Is heat-resistant and high unsaturated fats, however it comes with an omega ratio of 1:311. Yep that’s a 300 there. It is still good for your cholesterol levels, but a too high omega 6 level can impact your inflammation markers negatively.

A better option for frying therefore is canola oil, also called rapeseed or colza oil. It is still very heat-resistant (smoke point at 242° C) and can be used for deep-frying as well. It is super low on saturated fats and brings your omegas in a fantastic 1:2 ratio. Compared to some other super healthy oils, canola is very affordable and can be used as your day-to-day oil, as its footprint is super positive as long as you don’t take too much of it.

Oils rich in omega 3

If you want to boost your omegas, you should go for either chia oil or flax seed oil. Those oils come with an extreme 3:1 and 4:1 ratio of omega 3 to 6. Yes, that’s 4 times the amount of omega 3 than 6. This is so good, that you can use them to actively push your fatty acids into a healthy balance, even after eating bad fats before. Just make sure to not take too much overall, and make sure to only use this oil cold, since it is very sensitive and breaks at low heat.

One teaspoon of flax seed oil already overshoots your omega 3 need. If you sprinkle it on your salad, or give a little into your smoothie, your job is done. Use them as a secret weapon to get a healthy fat balance.

What about olive oil?

Olive oil comes with high amounts of unsaturated fats. However, the ratio between omega 3 and 6 is around 1:9, so not in the ideal range. It still is a valuable oil with a lot of nutrients inside and can be used with no problems.

The smoke point of olive oil is at around 200° C, so it is okay to use it for frying on low heat. Make sure to not heat it up too high or for too long and you should be good.

Nuts & Seeds

Generally speaking: all nuts are wonderful sources of unsaturated fats and bring you many vitamins and minerals on top of that. You should snack them frequently, but in moderation as well.

On average 70% of their calories come from fat. Since they are hard to digest, not all their calories reach our blood flow. Therefore, adding some nuts and seeds to your meals or having them as a snack in between, is always a good idea. Just make sure to not use them as your main source of energy during the day.

In terms of omega fatty acids, you should put some special focus on walnuts, chia and flax seeds. Walnuts deliver omega 3 and 6 in a 1:4 ratio, so they are on spot. One hand full of walnuts can already cover your daily need of essential fats. Snack them in-between, add them to your cereals or crumble them on salads. There’s so many ways of incorporating them into your diet. Make sure you have them at home and make use of them frequently.

Flax, Chia are the jackpot in terms of fats. Try to have plenty of them. Walnuts as well can boost your omega 3 in no time.

Like with their corresponding oil, chia and flax seeds are real omega 3 boosters. Add them to your breakfast cereals or use them in salads. Let them be your foundation of healthy fats.

You absolutely should buy flax seeds. They are cheap, widely available and can be stored for a very long time. Flax seeds however are hard to digest and if you don’t chew them properly, you won’t be able to access all of their goodies. To make sure you can access the good oils, you should grind or blend them.

Once ground, light and heat can easily destroy them. I recommend having a sack of whole flax seeds at home and grind the amount needed for a week. Just transfer them to a jar and store them in the fridge. You then pick what you need and put the glass back to keep the oils protected. You can also buy ground flax seeds directly, but usually they are overpriced. Just get some cheap flax seeds and do the job yourself. it literally takes you two minutes per week.

Fish & Seafood

From a fat perspective, most fish and seafood are excellent sources of omega 3. Fish is less calorie dense overall and brings fat in a good composition. You can use it as your base for a healthy fat supply. Keep in mind that some seafood like shrimp have as high cholesterol levels as eggs.

However, fish and seafood are often high in unwanted substances like mercury, antibiotics and more, which are directly linked to negative health impacts.

Generally, fishing comes with many problems. When looking at wild fish, we face the fact that we are overfishing the seas. In aquacultures parasites and excessive use of antibiotics to counter that problem make fish a less attractive source of good fats.

You can consider fish and seafood in general a good source of healthy fats. Don’t ruin it by having it fried all the time. And eat with moderation, if at all.

Overall: Yes, fish is a good source of healthy fats, but you still should moderate your intake because of unwanted substances, especially if you don’t know the source of the fish.

Meat and Chicken

The fatty acid profile of meat and chicken overall is “okay”, but often does not follow a healthy composition. Meat from mammals like cows, pigs and lab usually is above the 1/3rd threshold for saturated fats, while chicken usually is slightly below the line. You generally will find good amounts of omega 6, but will lack omega 3. Most meat from mammals provides around 2/3rds of their caloric value from fat. On top of that, you usually find fair amounts of cholesterol.

Poultry on the other hand is much lower in overall fat contents provided you eat the plain meat. If you add skin or fatty bits, fats can make up to 50% of the total calories.

While poultry is showing a better profile than red meat, you can as well make a difference by focusing on lean meat rather than fat pieces or even processed foods, where smoke, salt and preservatives are added. Quality here indeed can make a big difference.

You can see: chicken is better than red meat in terms of fats. Still, not an prime example of what fats can be. Eat in moderation, if at all

Overall you should limit your meat intake, especially for red and processed meats. The world cancer research fund recommends eating no more than 3 portions (350-500 g) per week. You can reach that with one steak already.

Dairy and Eggs

If you follow a vegetarian diet and rely strongly on, milk and cheese, then this seems to be bad news for you. Overall, all dairy products are super high in saturated fats. They still may bring omega 3 and 6 fatty acids in a good ratio most of the time, but only in very little amounts and at the cost of high saturated fats.

On top of that, milk products (and especially eggs) are high in cholesterol. Most milk products bring more than 50% of their calories from fat. I highly recommend eating those with moderation. You can lower the impact of dairy products by choosing low fat, skimmed variants of your food or by replacing it with plant based alternatives completely.

Clearly, you want to go short on Milk products. There is nothing beautiful about their fat profile. Eggs are okay-ish, but overall still a fat food.

Eggs in general deliver around 60% of their calories from fat. While the saturated vs unsaturated fat ratio is on spot (ca 30% of the fats are saturated), the omega 3 to 6 ratio lays at around 1:20. On Top of that one large egg already delivers 189 mg of cholesterol.

Grains and legumes

This group is generally low in overall fat, so their impact on your fatty balance is rather little and you can eat plenty of them. Soy marks one of a few exceptions with a whopping 40% of calories provided from fat. Still, it is made from around 60% of water, so the overall impact is still very little.

When looking at grains, the overall omega 3 to 6 ratio lays in between 1:10 and 1:20. Due to their low fat density however, this won’t be enough to bring you out of balance, if you manage to kick start your day with food that follows a good ratio.

Legumes on the other hand have their fats in a better composition. The pack is led by black beans with a ratio of around 1:2, while chick peas make the negative exception and bring your omegas with a 1:25 ratio on the table.

Overall uninteresting, but eating many legumes can contribute well to your overall fatty profile.

In summary, you should make sure to get most of your calories from these groups. The overall fatty profile is just great and if you eat them with variety, you will be doing just fine.

Fruit and vegetables

The fat content of fruit and vegetables mostly is on spot, but the overall caloric density paints a super low impact on your fat intake. You should eat fruit and vegetables whenever you can, but not as a reliable source of your dietary fats. After all, fruit and vegetable carries much water and is in general very light.

Except for avocado, nothing to worry about here. The overall caloric density is low. Hop Hop. Move on!

Just avocado should get a special mention here, as it is extremely high in unsaturated fats and bring around 80% of their caloric value from fats, which are mainly unsaturated.

Putting things practical. Tips for getting your fat under control

Now that we understand the fat in our foods, we can derive some practical tips from the lessons learned:

  • Use oils with care. A spoonful of oil can already add more than 100 kcal to your meal.
  • Choose plant oils over animal fats or tropical fats.
  • Three very good picks in oil:
    • Flax Seed oil. Do not heat at all. Excellent omega proportions that lowers your cholesterol. One tablespoon already covers your omega 3.
    • Canola oil. Good for frying and still super healthy. Mainly unsaturated fats with a whopping 1:2 ratio in omegas.
    • Olive oil. Good source of unsaturated fats that can be heated moderately. You should not solely rely on olive oil as it is slightly omega 6 heavy (ratio 1:9).
  • Eat meat, especially red meat with moderation, if at all.
  • Fish and seafood are generally a good source of fat in a healthy composition. Since they often contain unwanted substances, you might want to consider moderating your intake though.
  • Milk and dairy products generally consist of bad fats. Try to eat with moderation, if you cannot avoid them at all.
  • Eggs have a relatively neutral fat profile, with a slight overweight on omega 6 fatty acids. Around two thirds of the calories provided come from fat, so you should eat them in moderation as well, if at all.
  • Eat plenty of nuts and seeds. Snack them in between or crumble them onto your dishes.
  • Give Flax, Chia and Walnuts some special attention. They can positively impact your fat balance and give you an omega 3 boost. Try adding them already to your breakfast, for example in your oatmeal.
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