Lots of contradictive information about fats and oils can be overwhelming. What are good and bad fats? Which oils are healthiest to cook or fry with? And which should be avoided? Here is little guide for you about fats and what you should know when choosing oils.
Smoke point – does it really matter?
First, don’t be misled by smoke point of oils. High smoke point doesn’t mean that the oil can’t be oxidised and become rancid (toxic) at lower temperatures. It’s not about at what temperature your oil will start burning. It’s about structure and stability of the oil at high temperatures. We have three different types of oils: saturated, monounsaturated or polyunsaturated (omega 3 and omega 6).
A bit of chemistry behind fats and their stability at high temperatures
Saturated fats as are the most stable at high temperatures. From chemical point of view, a fatty acid is basically chain of carbon and hydrogen atoms with acid group at the end. The number of bonds between carbon and hydrogen determine if the fatty acid is saturated (no double bonds), monounsaturated (one double bond) or polyunsaturated (multiple double bonds). The more double bonds (polyunsaturated fats) the more unstable and more toxic fat can become when heated.
So why saturated fats are considered as unhealthy?
Excess of saturated fats may disrupt your cell membrane function. They got bad reputation because of the link with heart diseases. Nevertheless, saturated fats are the safest for cooking and frying. If you look at the bigger picture how cardiovascular diseases are developed, you will see that saturated fats are just tiny bit comparing to other major factors like chronic inflammation, oxidative stress, weight, lack of certain vitamins and much more.
What are the healthiest cooking oils and which should be avoided?
Having said that we just need to be careful what type of fat we choose for what purpose. If it’s for salad, sautéing, cooking or frying
- Coconut oil is my absolute winner. Butter and palm oil (only if not hydrogenated) are safe for cooking at high temperatures too. These are mostly saturated oils.
- Olive oil and avocado oil (mostly monounsaturated) are great for salads. They could be used for sautéing at low temperatures too. You don’t really measure temperature of your frying pan when you cook right? Unless it’s oven when you can set certain temp. Personally, I’m avoiding heating these oils too. I use them only raw for salads or as topping for cooked/roasted veggies. I would say staying on the safe side:). The less exposure to light, oxygen and temperature the better to fully preserve structure and health benefits of the oil.
- Vegetable oils like sunflower oil, flax seed oil, soybean oil, safflower oil and grapeseed oil are mostly polyunsaturated. These are least stable and worst for cooking. Cooking is one thing but in terms of vegetable oils, it’s worth to mention that they are very common in packaged food and snacks. Polyunsaturated fats like sunflower oil are very sensitive and can turn into harmful trans fats very easily when processed. I was trying to find crisps i.e without sunflower oil and I really struggled so if you know any good brands let me know!
Saturated vs unsaturated – how to choose cooking oils?
With oils it’s never black and white. By this I mean that none of the oils is 100% saturated or 100% unsaturated. Usually it’s a mix of three different types of fatty acids. When you choose your oil just look on how much percentage is saturated fat, how much is monounsaturated and how much is polyunsaturated.
In general the more saturated oil, the more stable and most suitable for cooking. The monounsaturated fats come next. Less stable than saturated fats but still better choice than polyunsaturated fats in terms of heating them. The worst choice for cooking would be polyunsaturated oils. I put this little table with most commons oils so hopefully it will make things more clear
Polyunsaturated fats (omega 3 & omega 6): good or bad?
It’s also worth adding that vegetable oils (polyunsaturated fats) are only bad for you when heated. They are considered as essential fatty acids as your body can’t make it and they should be provided with the diet. They are the one that make up your cell wall and make the cell fluid so more nutrients can enter the cell. In contrast too much of saturated fats makes cell wall rigid and less fluid.
So don’t avoid vegetable oils, just consume them raw and store them in cool dark place. Another point to consider is ratio of omega 3 and omega 6 in your diet. The optimal ratio is between 1:2 to 1:4. Nuts, processed meats and most of vegetable oils are high in omega 6. Always make sure you balance high omega 6 intake with omega 3 rich foods like flax seeds, chia seeds, hemp seeds, oily fish (wild salmon, mackerel or sardines).
Toxicity of oils
What happens when you heat inappropriate type of oil too much? They simply become oxidised, generating lots of free radicals and harmful compounds like aldehydes. Oxidised or hydrogenated oils are also called trans fats. Hydrogenation is basically converting liquid vegetable oils into more solid structure so they can be used for various purposes in the food industry. Oxidised fats disrupt cell membrane function, negatively affect cholesterol profile and blood vessel function. They are linked to insulin resistance and poor glucose metabolism too.