A DIETITIANS GUIDE TO COOKING OILS
As Dietitians we get asked about oils all the time - What is the best oil to use? Is it safe to cook with them at high temperatures? How much should I have?
Cooking oils are plant-based fat additions that often come from nuts, seeds, olives, palm and coconut. Each oil variety has its own unique flavour and nutrient profile, so it can become difficult to choose which one is best.
What to look out for in a healthy cooking oil
We have three main categories of fats in foods; saturated, monounsaturated and polyunsaturated. The idea is to decrease the amount of saturated fat you consume and replace it with monounsaturated and polyunsaturated fats. Saturated fat is found in animal products such as ghee, duck fat, chicken skin, fat on meat and butter, as well as coconut and coconut products. We also have another type of fat called a ‘trans’ fat. These fats are often hydrogenated (hydrogen is added to a liquid fat to make it solid), which changes not only the texture of the product but also its chemical makeup. These fats are not great for us and should be reduced (or avoided where possible).
When it comes to heating oils, in particular smoke points, there is a great deal of confusion. Heating an oil above its smoke point (which is the point at which you see ‘smoke’ rising from the oil) increases the likelihood that it will oxidise. However, smoke points vary between even the same types of oil and are a poor indicator of how that oil will change overtime. Have a read of this article summarising the evidence on what happens to oils when they are heated. Note they are all stable for about an hour!
Why is extra virgin olive oil our favourite choice?
Extra virgin olive oil, also known as EVOO is different to every other oil in the fact that it is basically the ‘juice’ from olives, has not been heavily processed and is naturally high in antioxidants, particularly polyphenols and vitamin E. Not only have antioxidants been known to fight off free-radicals and prevent disease, but research suggests that their anti-inflammatory effects can assist in weight maintenance, body composition, brain health, pregnancy and lactation. We should also point out that EVOO and olive oil are different! Olive oil (or pure olive oil or light olive oil) use lower quality olives and are refined, meaning the antioxidants are often removed (or their content decreased) and the health benefits are reduced. A common myth about EVOO is that it has a low smoke point and therefore should not be used for cooking. This myth has been dispeled by research, and in fact the polyphenols in EVOO protect it and keep it stable at high temperatures. Have a read of these informative articles by Dr Joanna McMillian and the Olive Wellness on the health benefits of EVOO and cooking with EVOO.
