When it comes to cooking with oil, it can be hard to figure out exactly what we should be using. After all, oils containing saturated fats were once considered to be unhealthy. However, studies have now proven that they’re harmless and in most cases better for us than other oils. That's why you will always see me recommending things like coconut oil or olive oil in my F.I.T. programs. What many people don’t realise, that while an oil may be healthy in its raw form, as soon as it’s heated the chemical make-up can change, transforming it from an oil that’s safe to consume into one which should be avoided.
If you’re planning to cook at a high heat, you should aim to use oils that don’t easily go rancid or oxidise. When oils oxidise they’re reacting with oxygen, forming harmful compounds and free radicals which are dangerous to our health.
When we begin to determine how resistant an oil is to rancidification and oxidation, both at low and high heat, we want to check how saturated it is with fatty acids. The fatty acid molecules of saturated fats only have single bonds, while those in monounsaturated fats have one double bond, and the fatty acid molecules in polyunsaturated fats have two or more.
While Monounsaturated and saturated fats are relatively resistant to being heated, oils which are high in polyunsaturated fats should generally be avoided if you’re planning to use oil for cooking.
Here’s a breakdown of some of the most common oils and how they compare when it comes to cooking.:
Coconut oil is the current health fad when it comes to oils, and you’ve probably read numerous articles and blog posts about how great this oil is and how it can be used for everything from moisturising your legs to making your hair soft and smooth.
This oil is rich in lauric acid which is thought to improve cholesterol and can be stored in your cupboard for months or even years. If you’re watching your calories you may want to go easy on the coconut oil as it’s high in saturated fat (one of the things that make it so heat-resistant), but it also boosts metabolism and can help you feel fuller compared to other oils.
Best for: Coconut oil is best for meals which require low to medium temperatures like stews, soups, baking, curries and raw desserts.
Canola oil comes from rapeseeds, although the uric acid (which is both toxic and bitter) has been removed. Most of the fatty acids in canola oil are monounsaturated and it’s high in Omega-3 fatty acids.The problem? Canola oil goes through a very harsh (and quite disgusting) processing method while it’s being turned into the final product and goes rancid easily, so it should be stored in a dark, cool place.
Best For: Canola oil is able to be used over high heat, making it a versatile option, especially for cooking meals like stir-fries.
Most people know that olive oil is great for our hearts, and recent studies have shown that olive oil can improve health biomarkers. It raises good cholesterol (HDL) and lowers oxidised LDL cholesterol (the bad kind that circulates through our bloodstream). Extra virgin olive oil is the best tasting olive oil and also has even more antioxidants.
Olive oil is unsuitable for cooking at high temperatures as it creates unhealthy trans fats when heated. If you’re planning to cook with olive oil, be sure to use it only at lower heats.
Best For: Olive oil is great as a salad dressing and is best for cold dishes. Try it mixed with a little balsamic vinegar or lemon juice over a salad for a healthy meal.
Butter has made a comeback. What was once subject to health warnings is now becoming more popular once again as studies show that real butter is good for us and actually a nutritious way to get vitamins E, A and K2. When choosing between processed margarine and butter, choose butter for its health benefits, though grass-fed is best, or unclarified butter like Ghee.
Best For: Butter is great for baking and cooking, however due to the tiny amounts of proteins and sugars it does tend to burn if you’re frying or cooking at high heat.
We were once told that vegetable oil was “heart-healthy”, but this couldn’t be more wrong. Recent studies have linked vegetable oil to cancer and heart disease, and many vegetable oils contain up to 4.2% trans fats which are actually highly toxic. Try not to avoid vegetable oils at all cost (or any other industrial and highly processed seed oils) and avoid them as much as you can. The problem is this oil sneaks into so many processed foods you wouldn't even think of, like biscuits, crackers, or even your beloved store bought nut milk.