Supermarket shelf full of vegetable oil

Eat Real Food. Part 1 – Dietary Fats

It is little wonder to me that many people are confused about the guidelines for healthy eating. We are constantly bombarded with contradictory information and studies regarding what is healthy and what will kill us. We have been told to lower our fat consumption, eat our 5 (or is it 7?) portions of fruit and veg daily, eat whole grains, go vegan, go carnivore or ketogenic and so on. I believe that most people who care about their health also care about what food they put in their bodies. So what should we eat if we are conscious of making healthy choices? In short, “real food”.

When diet is wrong, medicine is of no use. When diet is correct, medicine is of no need.

It’s taken me a long time to write a blog about the subject of real food. There is just so much to say. In the end I realised I had to break it down to a number of different blogs on the subject. So, here is the first of the “Eat Real Food” series. Dietary Fats.

The Demonisation Of Fats

I’m giving my age away here, but I remember that back in the 1980s we were told that we had to reduce our consumption of fats, especially saturated fats. There were TV adverts showing saturated fats blocking drain pipes with the implication being that it was doing the same thing to our arteries, causing a rise in heart attacks. Not only that, but fat is high in calories and over consumption is contributing to the obesity epidemic. I mean, it’s obvious isn’t it? If you consume fat you will get fat!

Saturated fat on a spoon
Saturated fat

Neither of these assertions turns out to be true, as I will explore later. But first, we need to understand more about fats.

Different Types Of Fat.

Fats are either saturated, monounsaturated or polyunsaturated. These definitions refer to the molecular composition of the fatty acids. A fatty acid is a chain of carbon atoms with hydrogen atoms attached, see the diagram below:

Molecular structure of fatty acids
Molecular structure of saturated, monounsaturated and polyunsaturated fats

From the diagram you will see that a saturated fatty acid has single bonds between the carbon atoms and each has 2 hydrogen atoms attached, with the exception of the first, which has 3; this is known as the Omega end. So saturated means that it is saturated with the maximum number of hydrogen atoms. There are no double bonds between the carbon atoms which is the reason for the stability of saturated fat and gives it the property of being solid at room temperature.

A monounsaturated fatty acid has one double bond between carbon atoms, 9 carbon atoms away from the omega end. This is an omega-9 fatty acid. The single double bond means that it is less stable than a saturated fatty acid, giving it the property of being liquid at room temperature and a tendency to solidify at cooler temperatures. Olive oil is 83% omega-9.

Polyunsaturated fatty acids have more than one double bond between the carbon atoms. These are the omega-3, omega-6 and omega-7 fatty acids. The 3, 6 and 7 refer to the number of atoms that the first double bond occurs from the omega end. These double bonds mean that these fats will stay liquid even at cooler temperatures.

The double bonds in polyunsaturated fats are less stable, being heat and light sensitive, and prone to oxidation during processing, storage, cooking and even after human consumption. I will talk more about the impact of oxidation on human health, later.

Omega 3, 6, 7 & 9.

Saturated fats are used purely as fuel by the body, whereas Omega 3, 6, 7 and 9 polyunsaturated and monounsaturated fats serve an important role in cell membrane function and repair. 

Omega-3s are “essential” fats, meaning that the body cannot make them on its own; they have to be obtained through food. Omega-3 fats are believed to serve many beneficial functions, from improving heart and mental health to decreasing the amount of fat stored in the liver. People suffering from depression have been found to have low levels of omega-3 in the brain. To me, the most interesting property of omega-3 is that it is required the “turn-off” the body’s inflammation response, when it is no longer needed.

Omega-6 is another essential fatty acid. In contrast to omega-3s, it is required by the body to promote an inflammatory response to injuries and to support the immune system when it is under attack. A healthy ratio of omega-6 to omega-3 is believed to be somewhere between 1-to-1 and 4-to-1. This gives the body the ability to turn on and off the inflammation response as and when required.

Omega-7 fats can be made by the body and are therefore not considered essential fatty acids. They are believed to contribute to a healthy digestive system, skin, blood sugar levels and a healthy inflammation response.

Omega-9 fats can also be made by the body and are thus considered to be non-essential. Nevertheless, there are still benefits to consuming these fats, especially as Omega-9 fats are believed to lower inflammation and improve insulin sensitivity. High inflammation and low insulin sensitivity are the root cause of many chronic western illnesses, so don’t shy away from the extra virgin olive oil!

The Diet-Heart Hypothesis.

Hopefully you are still reading this and I haven’t lost you with the science bit, but I do feel that it is essential to have that basic understanding of how fats may be beneficial or detrimental to our health.

So why have dietary fats been demonised? Why have we been advised to consume low-fat diets and avoid saturated fats as if they carry the plague? Well, we have to go back to the 1950s for the source of that.

The idea that saturated fats cause heart disease was primarily developed in the early 1950s by Ancel Keys, a biologist and pathologist at the University of Minnesota. Heart disease had been on the rise since the early 1900s and was starting to reach epidemic level by the 1950s. Researchers had found that cholesterol was the primary component of atherosclerotic plaque in coronary arteries. The build up of this plaque narrows the arteries until blood supply is compromised causing a heart attack.

Ancel Keys
Ancel Keys

It was wrongly assumed that cholesterol was the cause of the clogging of arteries. Consumption of saturated fats such as butter and coconut oil raises the levels of serum cholesterol more than other fats. Ancel Keys believed that the consumption of saturated fats was the problem. He called this idea the “diet-heart hypothesis”.

To cut a long-story short, he set about to prove this hypothesis and conducted studies across many countries comparing their consumption of saturated fats and death rates from heart disease. He produced a graph showing a close correlation between these 2 factors in six countries.

Six countries graph
The notorious six countries graph.

The six countries graph, shown on the left, has since developed a level of notoriety, as there were many countries left off the graph that did not support this correlation, as shown in the graph on the right. It appears that Keys “cherry-picked” the data to support his hypothesis.

In September of 1953, President Eisenhower suffered a heart attack whilst he was in office and was unable to perform his duties for several weeks. This dramatically raised public awareness of the rising problem of heart disease to the American public and Keys was successful in convincing the American Heart Association (AHA) that fats, especially saturated fats, were the problem. (Eisenhower, in fact, smoked up to 4 packets of cigarettes per day; he suffered 7 more heart attacks until his death in 1969.)

The AHA produced dietary guidelines that recommended low-fat diets and eliminating saturated fats as far as possible. This approach was adapted across the western world and forms the bedrock of belief for most people today as a “healthy diet”.

Vegetable Oils Are Seed Oils.

Vegetable oils, being polyunsaturated fats are promoted as heart-healthy. They’re derived from vegetables, so they must be good for us, right? Actually, they are not. Vegetable oils are extracted from seeds and are more accurately referred to as seed oils, which is what I will do from now on.

Sunflower oil depicted as heart healthy
Sunflower Oil depicted as "Heart Healthy"

So, what are these seed oils? They include rapeseed (canola), sunflower, soybean, corn, grape-seed and rice bran oil. Oils such as coconut, olive and avocado are actually derived from the flesh of the fruit and are not included in this definition; unlike seed oils, they are much healthier to consume.

History Of Seed Oils.

Seed oils weren’t originally used for human consumption. Their original purpose was to lubricate machinery after the use of whale oil became prohibited. Seed oil manufacturers saw an opportunity to sell this “lubrication” to the consumer and in 1911 Crisco created an animal-fat substitute using a process called hydrogenation, to turn the liquid oil into a solid fat, which they called margarine. Effective marketing persuaded the consumer that margarine was superior to butter for baking and cooking. The process of hydrogenation produces trans-fats which, some 90 years later, was recognised as being detrimental to human health.

Old advert of Crisco Margarine
Old advert for Crisco margarine

Due to the success of the diet-heart hypothesis in driving public health policy, natural saturated fats were replaced by hydrogenated oils and became widely used by the food processing industry during the 1970s/80s. This was attractive to the food processing industry as they were cheaper than using natural fats and sold to the consumer as healthier.

Nowadays in the home, restaurants and take-aways, seed oils are the fats of choice for shallow and deep-frying. They are used by most food processing companies and are very difficult to avoid. Take a look at the labels of most processed foods and you will most likely see sunflower or rapeseed oil listed in the ingredients.

So why is this an issue? First we need to take a look at how seed oils are produced.

Seed Oil Production.

When asked how these oils are produced I suspect that most people believe that the seeds, such as rape and sunflower seeds, are crushed and the oil is squeezed out of them and collected. In fact, it is quite difficult to extract oil from these seeds. After harvesting, the seeds are pressed using heat and high pressure. This extracts around ¾ of the oil with the remainder being chemically extracted by washing with a solvent.

Seed oil extraction
High pressure and heat to extract oil from seeds

The oil is then further washed with sodium hydroxide to remove impurities. The resulting oil is translucent, but cloudy, due to the presence of wax. This substance is cooled, allowing the wax to be removed for use in making vegetable shortening. The oil is then bleached to lighten the colour and a steam injection heating processes is used to remove the unpleasant odours. The oil is now “refined”. Yummy!

It goes without saying that this highly processed oil is not real food and the use of chemicals in its production cannot be healthy to ingest.

The Dangers Of Seed Oils

Aside from the dubious refining process in the production of these seed oils, there are other dangers in consuming them.

The first is the ratio of omega 6 to 3; remember, omega 6 promotes inflammation and omega 3 reduces inflammation. It is estimated that humans evolved on a diet that had an omega 6 to 3 ratio of around 1:1, whilst pre-industrial diets had a ratio of 4:1. The typical western diet today means that many are consuming a ratio of around 16:1 or even worse. Put another way the average human body now has over 20% fat as omega 6 vs just 7% 50 years ago.

Such a heavy omega 6 to 3 ratio promotes a state of chronic inflammation and is thought to be the main driver behind many of today’s chronic health problems such as heart disease, arthritis, Alzheimers, diabetes and inflammatory bowel disease.

Here are the omega 6 to 3 ratios in the most commonly used seed oils:

  • Sunflower oil – 40:1
  • Corn oil – 83:1
  • Grapeseed oil – 676:1
  • Soy oil – 8:1
  • Rapeseed oil – 2:1

As seen from the table above, only rapeseed oil has a healthy ratio. Unfortunately, it is also high in erucic acid (an omega-9 fatty acid) which is quite toxic to the human body.

The second issue is that, due to the multiple double bonds in the molecular structure, they are highly reactive and prone to oxidation, especially when exposed to heat and light creating free radicals, which damage cells. Imagine what is happening to the oil in your average fish and chips shop, where the food is deep fried in sunflower oil, which is reused many times before being replaced. 

Deep fat frying
Oil is often reused when deep-fat frying

Whilst heating accelerates oxidation, the double bonds in polyunsaturated fats means that they can easily turn rancid, just by being exposed to sunlight. This is why flax seed supplements (which have an excellent omega-6 to 3 ratio of around 1:5) are stored in dark glass bottles.

Polyunsaturated fats are not just used as fuel for the body they are also utilised in cells, which is why a high omega-6 diet can lead to chronic inflammation with all the associated health problems. Another side effect of this is the tendency to sunburn. I can attest to this from my own personal experience. Since avoiding seed oils I have noticed that I do not burn as easily when exposed to the sun. Sun exposure is vital for good health (the best way to get Vitamin D in the body), and I allow myself to get a natural tan as Spring progresses into Summer, without using sunscreen. I have found that I now get a tan without the soreness associated with sunburn. Granted, I live in the UK where the sun is not as strong as more southerly latitudes, but the point still stands. Could it be that oxidative damage in skin cells, caused by unstable seed oils, leads to an increased tendency to sunburn and skin cancers? Skin cancer rates have increased since people started eating margarine; whilst correlation doesn’t prove causation it is still interested to note.

The good news is that it is possible to lower the omega-6 levels in the body, by changing the fats that we consume – the change won’t be quick, it can take up to a couple of years to get these fats fully out of your body, but there’s no time like the present to start that process.

Avoiding Seed Oils.

The first step in improving your health, by eating real foods, is to dramatically reduce, if not eliminate, the consumption of seed oils. This is easily done at home, but more difficult to do when you’re dining out. Recently my wife an I went for dinner in a local pub and we were asked if we had any food allergies/intolerances. Curious to see what the response would be, I replied that we wanted to avoid seed oils and explained why. The waiter disappeared into the kitchens and upon returning told us that meant that we had to rule out half the options from the menu: the salads used sunflower oil dressing and many of the starters were fried in sunflower oil – I was quite shocked at how prevalent it was.

The other difficulty is avoiding these oils when shopping for food. Salad dressings, mayonnaise etc. all tend to contain sunflower or rapeseed oil. No doubt because they are cheaper than olive oil. Even the more “luxury” items proclaiming to be “in olive oil” can also contain sunflower oil, presumably so that it stays liquid when stored in the fridge. The only way to be sure is to read the label.

Processed foods are the worst offenders. Not only do they contain seed oils but they tend to also be high in sugar and refined carbohydrates: an absolutely toxic combination for the body. The next time you’re in the middle aisles of a supermarket, pick up a packet of biscuits, read the ingredients to see what I mean, then put them back down again and return to the fresh food aisles.

Best Fats For Cooking.

The best fats to consume are those that are recognisable as real food. There is no clinical trial evidence that saturated fats are harmful to human health, so there is no need to avoid them. Saturated fats are used by the body as fuel. They are converted into ketones which are neural healers and protectors for the brain. In truth, fats derived from food tend to be a mixture of saturated, monounsaturated and polyunsaturated fats. They are in a form that nature designed and nature knows best. Here’s a list of fats that I now consume:

Grass-fed butter: make sure it is grass-fed as the omega-6 level is lower than butter from animals that have been grain-fed. The milk solids in butter have a low temperature burn rate, so it’s not ideal for frying food. Avoid spreadable butter as these are blended with 33% rapeseed oil.

Ghee: this should be made from clarifying grass-fed butter, to remove the milk solids, making it ideal for cooking at higher temperatures. Ghee tends to be expensive to buy, but is really easy to make at home. I will post a blog on how to make your own ghee.

Coconut oil: has a very high temperature burn rate and is great for cooking, with a wonderful taste. Whenever I make a Thai curry I reach for coconut oil.

Olive oil: a monounsaturated fat, not great for cooking due to a low burn temperature, but fantastic for salad dressings. Only use olive oil that has been cold pressed.

Avocado oil: similar in composition to olive oil, but with more saturated fats. It has a higher burn temperature so great for frying and roasting vegetables. It also has a buttery taste which is delicious for salad dressings. As with olive oil only use cold pressed avocado oil.

Beef dripping, lard and goose fat: yes, I’m serious. I have no qualms at all about cooking with these fats. They are natural, stable and taste great. Roast potatoes are not the same without them.

Low Fat Diets.

Whilst the above are great fats for cooking with, you should also aim to eat foods that contain these fats naturally. Don’t shy away from foods that are naturally high in fats. The low-fat diet encouraged since the 1980s has resulted in the general population getting fatter and sicker. Why?

I alluded to this earlier. It comes from the misconception that eating fats that make you fat. You can understand the correlation. Especially when you look at the number of calories per gram. 1 gram of fat contains 9 calories, whilst 1 gram of protein and carbohydrate each contain 4 calories.

Counting calories has become an obsession and has led to the call for manufacturers to reduce the fat levels in the food they produce. As fats taste good manufacturers tended to replace these fats with sugar to compensate on taste. The American Heart Association has produced a food pyramid placing carbohydrates at the bottom, making them as the main source of our calories, whilst putting fats at the top, keeping consumption to a minimum. This dietary advice has been replicated throughout the western world. Yet, look at some old photos from the 1960s and 1970s and notice how everyone appears to be slimmer than today.

Original USDA Food Guide Pyramid
Original USDA Food Guide Pyramid

It’s partially down to the advice outlined on the food pyramid. People have changed their diets to consume more carbohydrates and less fats. The assertion that weight gain is a factor of the number of calories consumed against the number expended though activity is a bit of a myth. It is a factor, but we are not bunsen burners, that is not how are bodies are fuelled. The creation of fat cells is more a function of hormones, especially insulin. Insulin is produced by the body to allow glucose, from carbohydrates, to be absorbed by the cells for burning as fuel. Insulin also creates fat cells, for reserves. If the body is overwhelmed by carbohydrates and the cells are “full” of glucose then the body becomes “Insulin resistant” and more insulin is produced to try the cram the glucose into overwhelmed cells. This increased insulin creates even more fat cells. So it’s not the high-fat that causes us to get fat, it’s the high carbohydrates – especially sugar and refined carbohydrates that are prevalent in processed foods.

It’s time to stop counting calories and return to eating real foods. Don’t shy away from natural foods that are high in fats. Fish, grass-fed meats, eggs, nuts, olives, avocados and seeds are all fantastic sources of omega-3, 6 and 9, in a form that is ideal for human health without the tendency for harmful oxidation. Real food, the way nature intended, is always better for our health. Nature really does know best.

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