You have many options when it comes to selecting fats and oils for cooking.
But it's not just a matter of choosing oils that are healthy, but also whether they stay healthy after having been cooked with.
When you're cooking at a high heat, you want to use oils that are stable and don't oxidize or go rancid easily.
When oils undergo oxidation, they react with oxygen to form free radicals and harmful compounds that you definitely don't want to be consuming.
The most important factor in determining an oil's resistance to oxidation and rancidification, both at high and low heat, is the relative degree of saturation of the fatty acids in it.
Saturated fats have only single bonds in the fatty acid molecules, monounsaturated fats have one double bond and polyunsaturated fats have two or more.
It is these double bonds that are chemically reactive and sensitive to heat.
Saturated fats and monounsaturated fats are pretty resistant to heating, but oils that are high in polyunsaturated fats should be avoided for cooking (1).
Alright, now let's discuss each type of cooking fat specifically.
The Winner: Coconut Oil
When it comes to high heat cooking, coconut oil is your best choice.
Over 90% of the fatty acids in it are saturated, which makes it very resistant to heat.
This oil is semi-solid at room temperature and it can last for months and years without going rancid.
Fatty Acid Breakdown:
Make sure to choose virgin coconut oil. It's organic, it tastes good and it has powerful health benefits.
Butter was also demonized in the past due to its saturated fat content.
But there really is no reason to fear real butter. It's the processed margarine that is the truly awful stuff (11).
Real butter is good for you and actually fairly nutritious.
It contains Vitamins A, E and K2. It is also rich in the fatty acids Conjugated Linoleic Acid (CLA) and Butyrate, both of which have powerful health benefits.
Fatty Acid Breakdown:
There is one caveat for cooking with butter. Regular butter does contain tiny amounts of sugars and proteins and for this reason it tends to get burned during high heat cooking like frying.
If you want to avoid that, you can make clarified butter, or ghee. That way, you remove the lactose and proteins, leaving you with pure butterfat.
Here's a great tutorial on how to clarify your own butter.
Make sure to choose butter from grass-fed cows. This butter contains more Vitamin K2, CLA and other nutrients, compared to butter from grain-fed cows.
Olive oil is well known for its heart healthy effects and is believed to be a key reason for the health benefits of the mediterranean diet.
Some studies show that olive oil can improve biomarkers of health.
Fatty Acid Breakdown:
Studies on olive oil show that despite having fatty acids with double bonds, you can still use it for cooking as it is fairly resistant to the heat (19).
Make sure to choose quality Extra Virgin Olive Oil. It has much more nutrients and antioxidants than the refined type. Plus it tastes much better.
Keep your olive oil in a cool, dry, dark place, to prevent it from going rancid.
The fatty acid content of animals tends to vary depending on what the animals eat.
If they eat a lot of grains, the fats will contain quite a bit of polyunsaturated fats.
If the animals are pastured raised or grass-fed, there will be more saturated and monounsaturated fats in them.
Therefore, animal fats from animals that are naturally raised are excellent options for cooking.
You can buy ready-made lard or tallow from the store, or you can save the drippings from meat to use at a later time. Bacon drippings are especially tasty.
Palm oil is derived from the fruit of oil palms.
It consists mostly of saturated and monounsaturated fats, with small amounts of polyunsaturates.
This makes palm oil a good choice for cooking.
Red Palm Oil (the unrefined variety) is best. It is also rich in Vitamins E, Coenzyme Q10 and other nutrients.
However, some concerns have been raised about the sustainability of harvesting palm oil, apparently growing these trees means less environment available for Orangutans, which are an endangered species.
The composition of avocado oil is similar to olive oil. It is primarily monounsaturated, with some saturated and polyunsaturated mixed in.
It can be used for many of the same purposes as olive oil. You can cook with it, or use it cold.
The best fish oil is cod fish liver oil, because it is also rich in Vitamin D3, which a large part of the world is deficient in.
However, due to its high concentration of polyunsaturated fats, fish oil should never be used for cooking. It's best used as a supplement, one tablespoon per day. Keep in a cool, dry and dark place.
Flax oil contains lots of the plant form of Omega-3, Alpha Linolenic Acid (ALA).
Many people use this oil to supplement with Omega-3 fats.
However, unless you're vegan, then I do recommend that you use fish oil instead.
Evidence shows that the human body doesn't efficiently convert ALA to the active forms, EPA and DHA, of which fish oil has plenty (20).
Due to the large amount of polyunsaturated fats, flax seed oil should NOT be used for cooking.
Canola oil is derived from rapeseeds, but the euric acid (a toxic, bitter substance) has been removed from it.
The fatty acid breakdown of canola oil is actually fairly good, with most of the fatty acids monounsaturated, then containing Omega-6 and Omega-3 in a 2:1 ratio, which is perfect.
However, canola oil needs to go through very harsh processing methods before it is turned into the final product.
Check out this video to see how canola oil is made. It is very disgusting and involves the toxic solvent hexane (among others) - I personally don't think these oils are suitable for human consumption.
There are many nut oils available and some of them taste awesome.
However, they are very rich in polyunsaturated fats, which make them a poor choice for cooking.
They can be used as parts of recipes, but do not fry or do any high heat cooking with them.
The same applies to peanut oil. Peanuts technically aren't nuts (they're legumes) but the composition of the oil is similar.
There is one exception, however, and that is macadamia nut oil, which is mostly monounsaturated (like olive oil). It is pricey, but I hear it tastes awesome.
If you want, you can use macadamia oil for low- or medium-heat cooking.
Industrial seed and vegetable oils are highly processed, refined products that are way too rich in Omega-6 fatty acids.
Not only should you not cook with them, you should probably avoid them altogether.
These oils have been wrongly considered "heart-healthy" by the media and many nutrition professionals in the past few decades.
Avoid all of them:
One study also looked at common vegetable oils on food shelves in the U.S. market and discovered that they contain between 0.56 to 4.2% trans fats, which are highly toxic (24).
It's important to read labels. If you find any of these oils on a packaged food that you are about to eat, then it's best to purchase something else.
To make sure that your fats and oils don't go rancid, it is important to keep a few things in mind.
Don't buy large batches at a time. Buy smaller ones, that way you will most likely use them before they get the chance to damage.
When it comes to unsaturated fats like olive, palm, avocado oil and some others, it is important to keep them in an environment where they are less likely to oxidize and go rancid.
The main drivers behind oxidative damage of cooking oils are heat, oxygen and light.
Therefore, keep them in a cool, dry, dark place and make sure to screw the lid on as soon as you're done using them.