4 tips for navigating your way through the aisle of cooking oils

Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.

It’s a jungle out there - there is certainly no shortage of choice when it comes to perusing the supermarket aisle stocked with cooking oils. We are bombarded with an abundance of different types, as well as different marketing messages and buzz words, such as ‘lite’, ‘cold-pressed’ and ‘extra virgin’. But, where do you start? Which ones stack up best for your health? And which ones should you be avoiding?

Oils play an important role in the diet – we use them for baking, frying, salads and marinades. They are also a source of fat which is essential for production of cells and hormones, as well as helping the body absorb nutrients. They come in two forms – solid (saturated fat) or liquid (unsaturated fat). 

Here is a review of the 6 most popular:

1. Coconut oil

Because coconut oil is about 80 per cent saturated fat, it’s solid at room temperature and not something we should be using with cooking. The big coconut campaign has been one of the best marketing scams of the 21 st century, but it shouldn’t be part of your diet.

Score: 2/10 – Government guidelines tell us to stay away from this stuff due to the negative effect that a high saturated fat consumption can have on the heart. Replacing sources of saturated with unsaturated fat will reduce your risk of heart attack.

2. Olive oil

Olive oil is obtained from the fruit of olive trees. Whether it be ‘extra virgin’, ‘virgin’, ‘pure’, ‘lite’ or ‘light’, all varieties of olive oil tick the box when it comes to nutrition. Olive oil is predominantly unsaturated fats - those fats that reduce the ‘bad’ cholesterol in the blood and decrease inflammation in the body. Better still, olive oil is largely made up of monounsaturated fatty acids and we want more of these fats in our diet.

Despite polyunsatured fats also being good for us, the modern-day Western diet has led to an unfavourable balance between omega-6 and omega-3 polyunsaturated fat consumption – a ratio as high as 8:1, which leads to inflammation. We get too many omega-6 polyunsaturated fats from oil and processed foods such as cakes, bakery goods, biscuits, and take-away foods. However, a diet rich is olive oil and fish will improve this ratio and see a 2:1 intake of omega-6 to omega-3 polyunsaturated fats, which decreases inflammation and improves health.

Extra virgin olive oil is the highest quality olive oil you can buy as it is extracted from the first pressing of olives and has not been subjected to temperature during extraction. Therefore, you often see ‘cold pressed’ on the label.

Score: 9/10 – You can use it for everything, but the smoking point – the temperature at which it goes rancid – varies between the different types of olive oil, which makes some varieties better than others for cooking.

3. Sunflower oil

Even though it’s not to be confused with safflower oil, these two oils have the same nutritional breakdown and are high in omega-6 polyunsatured fats. It is a versatile cooking oil due to its high smoke-point and light taste, which is why it’s commonly used for deep-frying, but it’s not something you should be putting in your shopping trolley. Research has also shown that oils rich in polyunsaturated fats, like sunflower oil, produce toxic substances known as aldehydes, which are detrimental to our health.

Score: 3/10 – Leave this oil on the shelves as there are much better alternatives.

4. Canola oil

Canola oil comes from the seeds of the canola plant – the same plants that produce the small, yellow flowers. It has a neutral flavour and high smoke point, making it suitable for baking and stir-frying. This oil is high in monounsaturated fat and makes up a large part of the Nordic diet - a diet proven to reduce your risk of heart disease.

Score: 8/10 – It has a similar nutritional breakdown to olive oil, but it’s often found in highly refined forms so it may not pack as many benefits as other oil selections. But, just like all the other oils, you can also buy canola oil unrefined or ‘cold pressed’ which contain a higher content of antioxidants than their refined counterparts. Its versatility should make it a staple in your cupboard.

5. Walnut oil

Extracted from walnuts, this expensive oil has a rich, nutty flavour which works great as a dressing or flavour enhancer. However, this is another oil that is high in polyunsaturated fats so stick to eating walnuts in their natural form.

Score: 4/10 – Enjoy nuts for what they are - a delicious and nutritious snack food.

6. Vegetable oil

Just because it has the word ‘vegetable’ in it doesn’t make it a healthy choice. In fact, vegetable oils fall towards the bottom of the list when it comes to choice. This highly processed and refined extraction of various seeds results in a flavourless and odourless oil which can be subjected to high temperatures. This makes it suitable for deep-frying, but much like many of oils from which it is derived – sunflower, safflower, sesame, peanut, cottonseed, palm – it is going to be high in omega-6 polyunsaturated fat and best left on the shelf.

Score: 4/10 – Vegetable oil is commonly used in baking, but canola oil is a much better choice.

Take home messages:

1. Ditch the vegetable oil and oils high in omega-6 polyunsaturated fat - swap for olive or canola oil.

2. Don’t let oil smoke when cooking. If it does, clean the pan and start again on a lower heat.

3. Use ‘extra virgin’ or ‘virgin’ when dipping bread, making salads, marinades and dressings.

4. Use a regular or ‘pure’ oil when cooking, or a ‘lite’/ ‘light’ oil, which is lighter in flavour.

About Dr Nick Fuller

Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.