The Truth About Cooking Oils

RFBoils_bannerMonounsaturated. Polyunsaturated. Saturated. Trans. Short chain, medium chain and long chain. Triglycerides. Cholesterol. Hydrogenated. Partially hydrogenated. Expeller pressed. Extra virgin.

Does anyone know what on Earth I am talking about?

If you said fats or oils, you’re completely correct.

Don’t despair – contrary to the complicated names, you won’t need to take a whole semester of chemistry to understand the truth about cooking oils.

The difference between fats and oils is the form it takes at room temperature.

Fats are solid, oils are liquid!

That’s not to say the subject isn’t daunting.  With fats and oils often being in the spotlight, there is a tonne of information out there.  And most of it is conflicting, some of it is controversial, and all of it is confusing.


Like all foods, the least refined and processed the oil or fat is, the better.  Fats and oils will never have zero processing, but the closer it is to nature, and the more ‘intact’ the fat is, the higher the quality. By intact, I am referring to fats that are largely undamaged and more complete/whole.

Disclaimer: This article is based purely on my own beliefs and knowledge.  Some of the information I present is quite controversial, and may not sit well with everyone.  This article is purely for informational purposes only and should not replace any advice given by health professionals to treat medical or nutritional illnesses.


Coconut Oil

In the last few years, coconut oil has been the target of a lot of hype.  Derived mostly from the flesh of mature coconuts, coconut oil is made up of around a massive 90% saturated fat.  There are many processing techniques used to extract coconut oil, however, we recommend using extra virgin, cold-pressed coconut oil, which has been gently processed, still retaining high quality fats.   

The Pros:

  • Is predominantly made up of medium chain fatty acids (a term that refers to how long the fats are), which can be easily broken down and used for energy in the liver, so are rarely stored within the body unlike longer fatty acids.
  • Contains almost 50% lauric acid, a medium chain saturated fatty acid which has been found to have many health benefits, including reducing heart disease risk, weight loss, and its antiviral, antifungal and antibacterial properties.  The only other natural source of lauric acid in such high concentration is breast milk!
  • Saturated fatty acids are extremely resistant to heat, light and oxygen.  This means that coconut oil will retain the high quality of its fats as they will not easily become rancid and form harmful free radicals. Saturated fats allow more efficient use and storage of omega 3s in the body.
  • A good high heat cooking oil.

The Cons:

  • Can be expensive.
  • The smell and taste may mean this oil is not suitable for all applications.
  • Contains some longer chain fatty acids that are harder to digest and are often stored within the body.
Olive Oil

Since the largely popular Mediterranean diet, olive oil has been a favourite in many kitchens.  Like coconut oil, we recommend using extra virgin olive oil.

The Pros:

  • Is minimally processed.
  • Is 75% oleic acid, an extremely stable monounsaturated fatty acid.
  • If cold pressed, it still contains a high amount of antioxidants.
  • Is great for a wide variety of applications.
  • In comparison to other common unsaturated oils on the market, olive oil is relatively low in omega 6 fatty acids.

The Cons:

  • Heating extra virgin olive oil may compromise both taste and quality of the fatty acids.
  • Contains some unsaturated fatty acids that are susceptible to damage from heat, light and oxygen, and may become harmful to health.
  • Contains longer chain fatty acids, which may contribute to the build up of body fat.

The use of butter has been traced back over 2,000 years, and is a large part of a traditional diet.  In the last century, butter has been placed on the backburner as a food of choice as saturated fat has been condemned of causing heart disease.

The Pros:

  • Extremely nutrient dense, containing all of the fat-soluble vitamins (A, D, E and K), as well as a wide variety of minerals.
  • Contains a large portion of short and medium chain fatty acids that are easily digested and converted straight into energy (therefore, not stored as fat).
  • Contains some lauric acid (the fatty acid found in coconut oil that has many health benefits).
  • When made from pasture fed cows, the quantity of omega 6 and omega 3 fatty acids is equal, preventing the imbalance of omega 6 that causes health problems.
  • Butter contains components that are essential for brain function, gut health, to produce steroids and hormones, and prevent inflammation.
  • Has a beautiful taste, and is also pleasant smelling.

The Cons:

  • Lower grade butter made from grain fed cows do not contain as many of the health qualities of pasture-fed butter.
  • Pasture-fed, organic butter can be expensive.
Macadamia Oil

A great tasting oil that is often used for its skin and hair health benefits.

The Pros:

  • Contains a high amount of oleic acid, the same beneficial monounsaturated fatty acid found in olive oil.
  •  Many macadamia oils are Australian products.
  • Doesn’t require harsh extraction or chemical processing.
  • Is relatively resistant to damage from heat, light and oxygen (although I still recommend storing it in a dark glass jar or box in the fridge).
  • Has a low omega-6 fatty acid content.
  • Is rich in antioxidants.
  • Can be more neutral in flavour than extra virgin olive oil.

The Cons:

  • Is not appropriate for high-heat cooking.
  • You can get all the same benefits, plus more, from eating the whole nut.
  •  Lower grade macadamia oil is not as beneficial to health. Ensure you are buying extra-virgin or cold-pressed macadamia oil.  It should taste buttery and be golden in colour.


Flaxseed Oil

Over the last few years, flaxseed oil has flourished on the market – sold as a medicinal supplement that is supposed to reduce the risk of heart disease and inflammation due to its high omega 3 content.

The Pros:

  • Is rich in omega 3 fatty acids, so the oil can be beneficial as an omega 3 supplement, especially for vegetarians/vegans.

The Cons:

  • Its high level of unsaturation means that it is extremely susceptible to heat, light and oxygen damage.
  • It is unsuitable for cooking.
  • Has a short shelf life.  I recommend buying small bottles of flaxseed oil, storing them in the fridge in the box they come in, and consuming it within 6-8 weeks.
  • Good quality fish oil and fresh fish also have a great omega 3 fatty acid profile, plus more other health benefits, than flaxseed oil.
Grapeseed Oil

Grapeseed oil* has been adopted by the health industry as a ‘healthy’ oil to use for cooking, baking and salads.

The Pros:

  • Is pleasant tasting.
  • The processing required to extract the oils from the grape seeds is not as harsh as the process for rice bran oil and other vegetable oils (although more than olive and macadamia nut oils).
  • Contains high levels of antioxidants.
  • Has a higher smoke point than olive oil (but I would still not recommend using it for cooking).

The Cons:

  • Contains higher levels of polyunsaturated fats than other vegetable oils.
  • Contains high amounts of omega 6 fatty acids.
  • It is susceptible to damage from heat, light and oxygen.
  • Can be relatively expensive.

*If you choose to use grapeseed oil over olive oil I would recommend buying small bottles (preferably one that comes in a dark glass bottle), and storing it in the fridge for a maximum of 8 weeks.


Canola Oil

Canola oil is a moderately new oil, developed mostly to feed livestock and for biodiesel from rapeseed.  A few years ago it was heavily marketed as being a “healthy” fat, and a better option to other vegetable oils.

The Pros:

  • Contains some oleic acid, the monounsaturated fatty acid found in high levels in olive oil.

The Cons:

  • Is highly chemically processed and refined, making the product chemical laden and void of nutrients.
  • Is often sourced from genetically modified canola (in Australia this should be mentioned in the ingredients list).
  • Contains high levels of sulphur that can be toxic and have undesirable health effects.
  • During one of the processing steps, some of the fats (the fragile omega 3 fatty acids) in canola oil are transformed into trans fatty acids (the guys that cause a lot of damage in our bodies).
  • Some studies have linked canola oil with health problems including; depressed immunity, vitamin E deficiency, and heart lesions.
Vegetable Oil

Vegetable oil is a generic term used for oils derived mostly from soybean, cottonseed, canola, safflower, corn, and sunflower.

The Pros:

  • Some varieties and brands can be high in omega 3 fatty acids* that are deemed to be ‘essential’.
  • Inexpensive to buy.

The Cons:

  • May be sourced from genetically modified ingredients.
  • Is highly chemically processed and refined, making the product chemical laden and void of nutrients.
  • Some studies have linked vegetable oils with cancer, asthma and heart disease.
  • Consumption has increased dramatically over the last 100 years, which has caused an imbalance in the crucial omega 6 to omega 3 ratio in our diets.
  • Has little vitamin or mineral value.

*The fragile omega 3 fatty acids may be transformed into trans fatty acids during the extraction and refining process of the oils.

Rice Bran Oil

Rice bran oil has been marketed as a ‘healthy’ oil based on its zero cholesterol and high antioxidant content.

The Pros:

  • Has a high smoke point (the temperature it reaches before ‘burning’), so is often used instead of canola for deep-frying in commercial situations.
  • Rich in antioxidants, vitamin E and plant sterols that somewhat prevent damage from heat, oxygen and light.
  • It’s relatively inexpensive.

The Cons:

  • Extremely highly processed and refined, as you can see by its ‘light’ colour and the absence of smell and taste.
  • High in omega 6 fatty acids.

Margarine is a relatively new product made from vegetable oils.  It has been designed to mimic traditional butter and marketed as a great option to reduce the risk of heart disease.

The Pros:

  • Some more expensive varieties contain plant sterols that may have certain health benefits.

The Cons:

  • The unstable, unsaturated fats become trans fats after hydrogenation (a process used to make margarine solid).
  • The vegetable oils are highly processed to produce the final product.
  • Contains many chemicals from the processing agents.
  • Most margarine no longer contains any of the vitamins and minerals from the original oils or plants used.

That rounds off my top 10 truths about cooking oils! Want more information on the slippery topic of fats and oils? Expand your kitchen know-how with the following resources (I’d love you to hear which fats or oils you choose to cook with and why).

  3. Fats and oils: formulating and processing for applications, 3rd edition. Richard D. O’Brien.