Consider the ‘smoke point'
When you heat oil it will begin to smoke at some stage – that's the 'smoke point'. And beware, if you chuck in a nice steak at this stage, the oil will spit, decorating your shirt with pretty yellow dots. Olive oil, while good in many ways, has quite a low smoke point and so isn't ideal when you're cooking steak, say, which needs a high temperature initially so the juice of the meat is ‘sealed' inside. Oils like canola, sunflower and grapeseed oil have lower smoke points and so are preferable if you're frying foods.
Consider the good fats
Monounsaturated fats lower total cholesterol as well as levels of bad cholesterol – and as a bonus they increase good cholesterol. Monos are found in macadamia, almond, avocado and olive oil. But again, these aren't necessarily the best fats to fry food with – the really good fats like monos are quite unstable and so don't respond well to heat. Oils containing polyunsaturated fats (sunflower and grapeseed oil, for example) are better to cook with as polys are more stable (ie they don't change so easily) than monos.
Consider your Ohs
Omega 3 is good for your heart, your brain and helps keeps your arteries clear – but just because olive oil is full of the stuff, don't think it's the only oil you should be eating. By heating olive oil the composition of the oil is changed, rendering all those 'good fats' bad. Grapeseed oils is also full of omega 3 but has a higher smoke point – so if you are going to cook with oil, opt for that instead. Keep using olive oil, but use it cold in salads or for lightly sautéing food on a low heat.
Consider sat fats
These are the bad ones that raise levels of bad (LDL) cholesterol. You'll find these in butter, margarine, and a huge amount in coconut oil. So this is to be avoided, right? Not necessarily. Saturated fats are the most stable and so are actually quite good to cook with when you need a high temperature (because their composition doesn't change as much as with other fats). Try mixing some butter with grapeseed oil for maximum benefits while frying food.
Consider trans fats
There are two types of trans fats: natural and synthetic. The natural ones aren't harmful; the synthetic ones are very bad indeed. Synthetic trans fats not only raise bad cholesterol, they reduce levels of good (HDL) cholesterol. They're formed by partially hydrogenating plant fats – some spreadable margarines, for example, contain up to 15% trans fat of their total fat content. To check your spread, read the fat content listing – if the figures listed don't add up to the total fat content, the missing grams of fat are likely to be trans fats.
(eg if the label says: 20g total fat, 10g sat fat, 2g polyunsaturates, 1g monounsaturates, it indicates that the rest – 7g – are trans fats.
The best advice is to avoid foods that list hydrogenated or partially hydrogenated fats on their labels – unless they specify they're trans fat free.
The right oil for your cooking technique
For hot pan-frying
Go for butter with a little squirt of grapeseed or sunflower oil. Butter does contain sat fat but that also means that when you heat it, it won't alter its chemical state as much as, say, olive oil. The squirt of oil helps prevent the butter from burning.
You can use butter again, but also nut oils such as almond or hazelnut, olive or sesame oil. Just make sure your ‘sautéing' doesn't turn into frying, which will cause the essential fatty acids in your oil to turn into toxic compounds.
All of those for sautéing, plus sunflower oil.
Tips to take away
If the fat smokes or burns it's toxic. Chuck it and whatever food was in it away.
The less manufactured an oil is the less unhealthy it'll be – opt for virgin or unrefined wherever possible.
Put water in the pan at the start of sautéing and then add the oil – that way it won't get quite so hot.
Use a non-stick pan, you'll need far less oil.
Use a spoon to put oil in a pan – just one tablespoon is about 120 cals. Measure each one and you won't overdo it by accident.
Use a spray oil to ensure you don't drown your food in fats.
Words by Siski Green