How do we get so many different oils from so many different foods?
Modern processes extract fatty acids using a mixture of heat and compression. Sometimes, extraction is cold pressed, which is a more minimal process. However, most sources of oil are not suitable for cold pressing. It would leave undesirable trace elements in the oil, causing it to be odiferous, bitter, or dark.
Cooking in oil has many advantages over alternative methods. Oil can handle far higher temperatures than water. Water tops out at 212°F/100°C, whereas oil can reach temperatures above 300°F/148°C. Higher heat means quicker cooking. But therein lies potential problems. Some oils, if not toxic already, can become toxic when heat rises above their smoke levels.
Frying in oil usually means a better heat transfer than 'dry frying'. Cooking surfaces are rarely uniform. A layer of oil heats effectively through conduction, retaining heat over a more even spread. Layers of air on uneven cooking surfaces heat less effectively through convection, essentially acting as insulation from the heat source.
Oils can also be used for dressing food like pasta and salads. We typically do this to make them easier to cut and consume, and for extra flavor. This can be a very healthy option, especially when combined with vitamins and minerals that require fat for absorption.
There are a lot of oils out there to choose from; some good and some bad. First, let's go over some bad ones to avoid, then we'll go over the good ones.
Grapeseed oil is the oil that is extracted from grape seeds. It usually comes from the seeds leftover from grapes used in the winemaking process. It's been growing in popularity over the years as it's cheap to produce, has high amounts of omega-6, and also contains vitamin E.
However, production can be a problem. Hexane, a toxic chemical, is often used to extract the oil from the seed. What you get from that is a toxic, mutated oil that loses many of its natural health benefits.
Grapeseed oil is around 70% omega-6 fats. Scientists speculate that a high intake of omega-6 fats, relative to omega-3s, can increase inflammation, which is connected to many other problems in the body. Furthermore, the vitamin E content is quite low.
With a moderately high smoking point, grapeseed oil is sometimes sold as a good choice for high-heat cooking like frying. However, this may be bad advice, as grapeseed oil is also high in polyunsaturated fatty acids. These fats react with oxygen at high heat, forming harmful compounds and free radicals.
Soybean oil is an edible vegetable oil extracted from soybean seeds. According to US agricultural services data, it is the most popular and largely used cooking oil in the world.
Soybean oil has a better fatty acid profile than grapeseed, with 50% omega-6, but comes with other concerns. Again it's largely extracted via hexane and at very high heats, leading to high toxicity.
Partially hydrogenated soybean oil is widely used in food processing due to its relatively low cost. Partial hydrogenation leaves trans fats, which should be avoided. If you buy, definitely consider paying a little more for fully hydrogenated.
However, with virtually no micronutrients in soybean oil, even if you find higher quality production, there are many far more healthier options out there.
Corn oil is a refined vegetable oil widely used in cooking, especially deep frying. It's about 60% omega-6 fats which again, is better than the fatty acid profile of grapeseed oil, but there are many concerns in the way it's produced.
Extraction from corn requires an extensive refining process. Heating at over 500°F/260°C massively adulterates its fatty acids, leaving a more toxic solution. Furthermore, most corn oil is GMO, which there are many concerns over.
Once again, there's virtually no micronutrients in corn oil. So even if you find higher quality production, there are many far more healthier options out there.
Sunflowers are one of the few crops native to the United States. Indigenous people likely began to cultivate them around 1000 BC.
With about 70% omega-6, it's as bad as grapeseed oil on the fatty acid profile, which you may remember, puts you at greater risk of inflammation.
If you're going to use sunflower oil, consider keeping the heat low and quick, but there's still a lot of oils out there with a much healthier nutrient profile.
Canola is an oilseed crop created through plant crossbreeding. It's only about 28% omega-6, giving it the best fatty acid profile out of all the oils covered so far. The problem is mainly in the processing.
Canola oil is produced from an inedible rapeseed using toxic chemicals. The seed processing uses synthetic chemicals like hexane to extract the oil. Again, most is GMO, and it has a very low nutrient profile.
Coconut oil is an edible oil derived from the wick, pulp, and milk of coconut palm fruit.
Amazingly, coconut oil is made up of 70% MCT fats. These are easily converted into ketones for energy as they require minimal processing by the liver.
Coconut oil is abundant in good fatty acids, primarily lauric acid which makes up 50% of its fat composition. Lauric acid is good for your immune system, provides an antifungal effect, and is known to remedy many ailments.
It has many phytonutrients, including polyphenols, which provide antioxidant benefits and support overall health.
Tallow is fat rendered from beef or less often mutton, which is why it’s sometimes called beef lard.
The healthiest tallow comes from grass-fed cattle, as opposed to those conventionally fed on grains, as this gives it a higher omega-3 profile.
Tallow rendered from grass-fed cattle is a great choice for metabolic and overall health, providing vitamins A, D, K, E and B12, choline, CLA and healthy fatty acids, including oleic acid, palmitoleic acid, stearic acid, linoleic acid and others.
Ghee is a clarified butter, often used in Indian cuisine. A high smoke point makes it ideal for frying and sautéing. It adds a rich, nutty flavor to dishes and is commonly used in traditional Indian recipes like curries and biryanis.
The process of making ghee involves simmering butter until water evaporates and milk solids separate. Solids are then removed, leaving behind pure, concentrated, golden fat.
Unlike butter, ghee is lactose-free and can be consumed by those with lactose intolerance. It also has a longer shelf life without refrigeration.
Loaded with omega-3 fatty acids and vitamin A, ghee also contains vitamin E, antioxidants, and butyrate, a short-chain fatty acid that supports gut health. Ghee has been shown to improve eyesight, reduce inflammation and boost your immune system.
Olive oil is low in omega-6 and high in monounsaturated fats, primarily oleic acid, which is known for its anti-inflammatory properties. Unlike many other oils, it does not contribute to inflammation and can, in fact, help reduce it.
Although low in vitamin and mineral content, olive oil is packed with more oleic acid and phytonutrients than coconut oil. It comes with many other healthy fatty acids, like linoleic and palmitic.
Olive oil has been shown to reduce LDL cholesterol buildup and lower blood pressure, which are vital benefits to those suffering from heart problems.
Extra virgin olive oil is obtained from the first pressing of the olives and is minimally processed, retaining more antioxidants and phytonutrients, and a richer flavor.
Avocado oil is one of few oils that's loaded with vitamins and minerals, especially potassium, a vital electrolyte most people are deficient in. Each avocado contains approximately 700mg of potassium, making it one of the absolute best sources out there.
Like olive oil, it's rich in oleic acid, a very healthy fat. Avocado oil has been shown to significantly lower levels of triglycerides, LDL cholesterol buildup, inflammatory cytokines and blood sugar. It enhances the absorption of important nutrients.
Rich in antioxidants, avocado oil helps fight free radicals - unstable compounds that can damage cells over time. You can easily add it to your diet in a salad, as part of a dip or marinade, or as a replacement for most other plant oils.
MCT oil is a supplement made from MCT molecules. MCTs are smaller than most fat molecules, making them easier for the liver and gut to process. MCT oil is usually derived from coconut or palm kernel oil. Both have MCTs in them. You can buy 100% MCT oil or a mixture of MCT and LCT.
MCT can help your body make ketones, allowing easier enjoyment of the extra energy and sharper mind that many people experience on a keto diet.
Be careful about consuming too much MCT oil if you're on a high carb diet, as the fat won't burn as well, and you may not get many of the benefits.
There are many different oils to choose from and it's a good idea to have a balance of the good ones. Where possible, choose unrefined, extra virgin, organic. Stay away from trans fats and check smoke temperatures. Refer back to the healthy summary information here and useful sources below if you’re unsure.
Grapeseed oil - https://www.healthline.com/nutrition/grape-seed-oil
Soybean oil - https://www.nutrition-and-you.com/soybean-oil.html
Corn oil - https://www.healthline.com/nutrition/corn-oil
Sunflower oil - https://www.healthline.com/nutrition/is-sunflower-oil-healthy
Canola oil - https://www.healthline.com/nutrition/is-canola-oil-healthy
Coconut oil - https://konsciousketo.com/blogs/keto/coconut-oil-ketosis
Tallow - https://draxe.com/nutrition/tallow/
Ghee - https://ghc.health/blogs/all-about-men/10-health-benefits-of-ghee
Olive oil - https://www.verywellfit.com/olive-oil-nutrition-facts-calories-and-health-benefits-4120274
Avocado oil - https://www.healthline.com/nutrition/9-avocado-oil-benefits
MCT oil - https://www.webmd.com/diet/mct-oil-health-benefits-common-uses