The dangers of cooking oils....and our Top 6 for good health.....

When you venture into the oils aisle of the supermarket, there are seemingly endless bottles of different types of oils, all claiming to be good for you. Combine this with the fact that we have been bombarded with so much misinformation about which fats are good and bad for us over the last couple of decades and it's understandable that people are confused about which oils and fats they should be using in their cooking. Does it even matter? Actually, yes, it matters a lot, as using the wrong oil can be damaging to your health. Our latest article lays down the facts you need to know, as well as the top 6 oils we recommend using in your kitchen to support good health.

What is an oil vs a fat?

Oils are fats in liquid form and are generally derived from plant sources. Fats on the other hand are heavier and mostly derived from animal sources (coconut & palm kernel oil being the exceptions) and are solid at room temperature.

A key difference between oils and fats is the types of fatty acid chains they contain, which define their flavour, texture and melting points. These chains have different numbers of double bonds which determine their straightness, or the number of bends they have in the fatty acid chains. The straighter the chain, the more saturated the fat is; the more double bonds, and therefore bends in the chain, results in fats that are more unsaturated.

The liquid oils contain more unsaturated fatty acids, and are either referred to as mono- or poly- unsaturated based on the number of bends they contain. These oils have a softer, more liquid form and are generally easier to digest. Monounsaturated oils, like olive and macadamia oil are liquid at room temperature but solid in the refrigerator. Polyunsaturated oils, like flaxseed, sunflower and canola, are liquid even at refrigerator temperatures. However, these oils are also more prone to oxidation, and require much more care in their handling and storage in order for their beneficial qualities to be in tact when we consume them. Animal fats tend to be more saturated, making them more solid and stable and less prone to rancidity.

Coconut and Palm Kernel oils are mostly saturated, however because they are comprised of medium chain fatty acids (MCFA's) this enables them to offer the best of both worlds, being more stable than the unsaturated fats but more easily digested and able to be used for energy easier than the saturated.

Our body uses each of these types of fatty acids differently and each offers different health benefits so it is recommended that we vary our fat sources between the polyunsaturated, monounsaturated and saturated types. Exclusive use of one type, or complete omission of another is not recommended.

But, is fat good for us?

Over the past 30 years or more, fat has had a bad wrap. After scientist, Ancel Keys concluded that eating saturated fat causes heart disease, low fat products and mono- and poly-unsaturated vegetable oils have flooded the supermarket shelves. In the last couple of years, with the realisation that this assertion wasn't based on sufficient research, and that in fact new studies are showing the opposite is actually true, things are slowly starting to swing back the other way, with fats no longer being painted as the baddie and people returning to butter from margarine. It will, of course, take a lot longer to completely undo the damage that has been done to fats reputation over the years, especially in regard to the widely held fear that eating fat makes you fat. In fact, we now know that most excess fat stored in the body is the result of eating sugar and not fat (Willmont D, 2007).

We also know that fat is extremely important to human health. It is a great source of energy, it provides the building blocks for our hormone and cell membrane production, it plays a role in cell-signalling, fuel for the brain, and it is required for us to absorb fat-soluble vitamins A, D, E & K, to name just a few of its vital roles. As well as this, fat provides flavour to our food, it satisfies our tastes and give us a feeling of satiety when we eat.

Natural fats and oils that we obtain from both plant and animal sources provide us with many different beneficial nutrients and should form part of a balanced diet. Polyunsaturated oils contain essential fatty acids (EFA's) which we are unable to make in our body, so are required to get from our food. They are important for normal growth and energy, thyroid and adrenal activity, immune support, healthy skin, hair and arteries, and many more functions. They are referred to as Omega-3 & Omega-6 fatty acids. Each type is important and has different roles in our body, for example Omega-6 fats encourage blood clot formation whereas Omega-3 fats reduce clotting. The ideal, is to achieve a balance between Omega-3 and Omega-6 fatty acids with the recommended ratio of Omega 3:6 being 1:2.

These essential fatty acids, however, are easily damaged, so although these vegetable oils are widespread in their usage, the EFA's in them are often rancid forms. If the oil is not treated correctly then these oils will oxidise and when ingested, will create free radicals in the body, leading to early ageing, weakened immunity and liver damage, and become a major contributor in chronic degenerative disease.

So, how do oils and fats become damaged and rancid?

Generally, the more unsaturated an oil, and the higher the amount of EFA's it contains, the more unstable it is and therefore, the more susceptible to damage. For example, Sunflower oil is much more unstable and more easily damaged than butter. At any point, from the extraction of the oil, through the processing, bottling, storing and cooking, it is vulnerable to damage.

There are 3 main things that can damage oils and fats:
  1. Light – the effect of light on oil is that it rapidly changes the unsaturated fatty acids into free-radical chains. Oils stored in plastic or clear glass bottles allow light to enter and ruin the oil.
  2. Oxygen - Oils stored for excessive periods of time in the presence of oxygen will become damaged and rancid so it is important to keep oils in a tightly capped bottle.
  3. Heat High heat can damage oil. Oils can be exposed to too much heat during extracting and refining processes, as well as during cooking and storage. EFA's are particularly prone to damage from heat, so oils that contain high levels of EFA's should not be used for cooking. Different oils can be heated to different temperatures before they become damaged and a good guideline to use here is their smoke points. The smoke point is when a heated oil starts to smoke continuously. It is worth noting also, that even before the smoke point, certain nutrients will already be lost, for example, vitamin E and other antioxidants are greatly reduced at much lower temperatures.
The smoke point of some commonly used oils is shown in the table below. The smoke point of unrefined oils is lower than that of refined oils. However, although a refined Sunflower Oil may have a much higher smoke point than one that is unrefined, this oil has already been damaged in the refining process so should be avoided anyway.
Smoke Point Temperatures
NB: When choosing an oil for cooking, consider the smoke point and the EFA content. Although Grapeseed & Rice Bran Oil, have very high smoke points, they also contain high levels of EFA's, whereas Avocado Oil and Ghee have high smoke points with low EFA levels, making them more suitable choices for high heat cooking.

What should I look for when buying oils and fats?

The quality of oils and fats that you buy is all important. To ensure good quality, we must consider how the oil or fat is treated at every stage: from how the plant or animal is treated, whether it is organic or grass-fed, how the oil is extracted, whether it is refined, how it is stored and then of course, how it is used in cooking.

There are many cheap oils out there, but it is definitely worth spending more to ensure you are getting a good quality one.

When buying oils, look for the following:
  • Organic – this means it should have minimal pesticide residue and should not be GMO. Generally, the nutrient content will also be higher.
  • Cold-pressed or expeller-pressed – this refers to the extraction process, indicating that additional heat was not applied to the oil during pressing and that chemical solvents were not used.
  • Unrefined – even though an oil may have been cold-pressed, sometimes it will undergo other processing afterwards in order to extend its shelf life. This can involve refining, bleaching, degumming and deodorizing, all of which apply heat and destroy the nutrients in the oil as well as sometimes adding harmful chemicals to it. If it is labelled 'Unrefined' then you know that this has not occurred.
  • 'Extra-virgin' Olive oil – The term 'virgin' indicates that the olives have been pressed purely by mechanical means, without the use of any chemicals. 'Extra Virgin' refers to oil with low acidity that is pressed within a very short window of harvesting the olives so that it retains a higher level of nutrients and flavour. The term 'Extra Virgin' does not guarantee however, that the oil has not been exposed to refining processes, so you should still check for 'Unrefined'. Avoid Olive Oils labelled, 'Pure', 'Light' and 'Extra Light' as these are lower grade and more likely to be refined.
  • Stored in a dark glass or sometimes stoneware bottles – to prevent exposure to light
When you are buying fats, look for the following:
  • Organic, preferably grass-fed animal fats which have higher levels of omega 3 fatty acids

Which oils and fats should I avoid at all costs?

  • Hydrogenated or partially hydrogenated – this process destroys unsaturated EFA's, creating unnatural trans-fatty acids, in order to extend shelf-life (almost indefinitely!), and changes the texture so that they are more solid but still spreadable and don't melt easily. Margarine, shortening and partially-hydrogenated vegetable oils are some examples of these. We are unable to break down these trans-fatty acids and they end up causing damage to our cells and interfering with many processes within our body.
  • Refined vegetable oils – these also contain trans-fats which are produced during the heat used in the refining process. Most prepared or fried food will contain refined oils and therefore trans-fatty acids.
  • Oils in clear plastic bottles – it doesn't matter if they are claiming to be cold-pressed, extra virgin or anything else, if they are in a clear plastic bottle then the oil will have been exposed to light for long periods. It also readily combines with plastic to form toxic plasticides (Pitchford P. 2002).
Above pic: Oils packaged in clear plastic bottles are exposed to light and can react with the plastic of the bottle forming toxic compounds.

How should I store my oils and fats?

  • Store in a dark bottle away from light. Keep tightly closed when not using. Most oils can be kept in a cool cupboard, but others like Flaxseed oil, with a high EFA content, must be stored in the fridge once open.
  • Fats should be stored in the fridge, however, if you want spreadable butter, cut a chunk off and keep at room temperature for the next day or two's use.

Our top 6 oils to use.....

You may have bought the best quality, organic, unrefined oil, but if you go home and overheat it through cooking then this kind of defeats the purpose. Here we recommend the top 6 oils to use and how:

  1. Avocado oil
    This is high in monounsaturated fats so it is more stable than most vegetable oils and therefore not as prone to oxidation and rancidity. It contains very low levels of EFA's and has a very high smoke point of 270C. Use for high heat cooking.
  2. Ghee – ghee is clarified butter, which is basically butter that has had the milk solids removed. It contains butyric acid which has been found to have antiviral and anti-cancer properties (Pitchford P, 2002). It has a smoke point of 250 C so is suitable for high heat cooking.
  3. Coconut oil - Coconut oil contains medium-chain fatty acids (MCFA's) which are easily broken down by our bodies to be used as energy. MCFA's are not stored as body fat. As it is 95% saturated fat it is virtually void of EFA's so you don't need to worry about damaging these when cooking, however, it works synergistically with EFA's in the body, doubling their efficiency and providing antioxidant protection for them. The high lauric & caprylic acid content gives it antimicrobial properties. It has a smoke point of 176 C so can be used for medium-heat cooking.
  4. Flaxseed oil – A great source of Omega 3 fatty acids, Flaxseed oil also contains lignans, a phytonutrient that contains phytoestrogenic and anti-cancer properties (Willmont D. 2007). Do NOT heat. Use for drizzling over food, salads, etc.
  5. Hempseed oil – contains a large amount of Omega 3 & 6 in a very good 1:3 ratio making it a great oil for regular consumption. It has a neutral taste and is high in other nutrients like magnesium, calcium, beta-carotene, sulfur and enzymes. Don't use in cooking due to the fragile EFA's.
  6. Olive oil – Olive oil is predominantly a monounsaturated fatty acid. It is high in antioxidants, phytosterols and polyphenols which have been linked to reducing the risk of heart disease and protecting the arteries (Willmont D. 2007). It can be used for medium-heat cooking but is best used raw, for drizzling over food, or in dressings, in order to retain the function of its beneficial nutrients and fatty acids.

    In summary:

    • Oils and fats contain many beneficial nutrients and properties. A combination of polyunsaturated, monounsaturated and saturated oils is recommended in order to reap a wide variety of these.
    • How an oil or fat is treated from the moment of extraction to the moment you eat it, is very important to ensure that it remains undamaged and retains its freshness and beneficial properties.
    • If oils and fats become damaged by exposure to heat, light or oxygen, they become dangerous to our health and should be avoided. Buy organic, expeller or cold-pressed, unrefined oils, and organic, preferably grass-fed fats.
    • Store oils in dark bottles in a cool, dark place. Store fats in the fridge.
    • When cooking at high heat, use Avocado oil or Ghee. When cooking at medium heat, Coconut or Olive oil can be used. For drizzling over meals, salads or in dressings, use Olive oil, Hempseed oil or Flaxseed oil. EFA's are easily damaged by heat so oils high in these should not be used for cooking.
    • The key to getting the best nutritional benefit out of oils and fats is to consume good quality oils and fats in moderation, which have been treated and stored correctly.
    I hope this article has been informative and useful. If you have any questions or would like further advice on anything to do with fats and oils, then please contact us at BodyNatured.

    Yours in good health, naturally! Victoria x


    • Worlds Healthiest Foods. (2016). 'Is it OK to Cook with extra-virgin olive oil'. Available at: http://www.whfoods.com/genpage.php?tname=george&dbid=56 (Accessed: 12th July 2016)
    • Pitchford P. (2002). Healing With Whole Foods: Asian Traditions and Modern Nutrition. North Atlantic Books. California, USA
    • Willmont D. (2007). Fat Chance: Surviving the Cholesterol Controversy and Beyond. Willmountain Press. Massachusetts, USA.


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