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Culinary oils can be a nutritious and delicious addition to any meal. Whether they’re used to create a crispy crust or drizzled on top of a meal to add flavour and depth. There are lots of different types of oils made out of fruits, nuts and seeds, animal products and even algae. So how do you pick the right cooking oil? That’s what we set out to explore.
Topics in this post:
Why we use oils in cooking
It’s possible to cook a meal using just water alone, so why do we use oils? The reason is two-fold, and it’s all about fat.
Fats keep your brain and body healthy. Nearly 60% fat makes up the human brain. Your brain and body need fats to keep you healthy. They’re a source of energy that helps you to perform at your best.
Fats are a group of chemical compounds with a similar structure that contains a key ingredient for our health: essential fatty acids (“fatty acids”). Our bodies need fatty acids for growth and to help to:
- Protect our organs
- Support muscle movement
- Reduce the risk of blood clots
- Control inflammation
- Support hormone production
- Increase vitamin and mineral absorption
Our bodies don’t make fatty acids, and so we need to get them from food sources like oils.
Fats add flavour, texture, and nutrients. Fats are a medium for flavours and enrich the texture of a meal. They also contain the vitamins and minerals that our body needs. (If you want to fall in love with fats, read Samin Nosrat’s book SaltFatAcidHeat and watch the “Fat” episode of her documentary series!). Oil (a type of fat) transfers heat from cooking surfaces to the food being cooked. We think oils are all-around delicious, whether you decide to use them raw for dressings or in your Instant Pot stew.
3 steps for how to pick a cooking oil
Picking the best oil for cooking depends on many factors. What’s best for one person may not work for another. We explain some key factors that should be considered all together to help you make your decision.
1. Choose a variety of fats to support your body
Our bodies are impacted by fatty acids in different ways depending on what type they are.
Unsaturated fats (the “good” stuff)
These “healthy fats” are liquid at room temperature and consist of two types: polyunsaturated and monounsaturated fats.
- Polyunsaturated fatty acids (PUFA), including Omega-3 and Omega-6 fatty acids, are unstable at high temperatures and not recommended for high heat cooking unless they are labelled “high oleic.” They become susceptible to oxidation, which is when fatty acids react with oxygen and start to break down and form harmful compounds like free radicals. Culinary oils include flaxseed, sunflower, walnuts, and more.
- Monounsaturated fatty acids (MUFA), including Omega-9 fatty acids, are more stable than polyunsaturated fats and can be used for cooking at higher temperatures. Culinary oils include peanut, soybean, rice bran and canola.
Saturated fats (the not so “bad” stuff)
These oils are solid at room temperature and resist oxidation, so they can be used for high-temperature cooking.
Increase risk of coronary artery disease is associated with a high intake of saturated fatty acids (SFA), and so they have been mislabelled a “bad fat.” However, recent studies show that saturated fats may not be so bad, even though they raise LDL cholesterol. When it comes to cholesterol, not all particles are alike. Small, dense LDL particles may create inflammation and artery blockages, but large, fluffy LDL particles can be protective.
Culinary oils high in saturated fat can also have other health benefits, including:
- Butter and ghee contain butyric acid that regulates your microbiome, supporting your energy metabolism and immune system;
- The body quickly absorbs coconut oil and metabolizes it for use as energy; and
- Palm oil contains beneficial nutrients such as carotenes and Vitamin E.
Industrially-produced trans fats (the “to avoid” variety)
These types of fats are a by-product of hydrogenation. The hydrogenation process turns vegetable oils into solids to extend their shelf life and stop them from going rancid (yuck, no one likes a rotten oil!). Consuming industrially-produced trans fat is associated with:
- Increased risk of coronary heart disease leading to heart attacks and strokes;
- Increased risk of Type 2 diabetes; and,
- Infertility in women.
Some spreads such as margarine and shortening include industrially-produced trans fats. The chemical compounds of some oils can also be transformed into trans fat when they are heated, such as during the industrial oil refining process (more on this below!). Dairy products such as butter contain naturally-occurring trans fat, but it’s generally considered to not have detrimental health impacts.
Avoid industrially-produced trans fat by:
1. Reading nutrient labels. Look for ingredients like “partially hydrogenated oils,” “hydrogenated oils” and “vegetable shortening.”
2. Limiting processed foods. Typically, the longer the ingredient list, the more processed a food is.
Using a balanced variety of fats is key. All oils are a combination of fatty acids. Eating a variety of monounsaturated (MUFA), polyunsaturated (PUFA), and healthy saturated (SFA) fat (like butter, ghee, coconut and palm oils) is important for your health. Focus on eating more omega-3 from sources such as oily fish, flaxseed oil, camelina oil, walnut oil, soybean oil and canola oil.
2. Pick the right oil for your cooking method
There are several ways to cook a meal—from sautéing and pan frying, to baking and roasting. Each cooking method uses a different temperature, and you can use the following table to pick the right one for your meal.
Oils do not get better with age. Oils have a shelf life and when they pass their expiry date, they go rancid. You can tell when oil is rancid if the smell and taste of your oil have changed (descriptors like old, stale, and strange come to mind…). This means that a chemical change has occurred and your oil is starting to decompose. Don’t eat it!
Every oil has a smoke point
Oil’s chemical composition changes when it’s heated and, if overheated, oil can pass its smoke point. When oil starts to burn and smoke, it breaks down and releases toxic fumes and harmful free radicals that are unhealthy to breathe and eat. (That’s right, even high quality and premium oils can become toxic when overheated). Going past the smoke point also harms food’s flavour and degrades nutrients. As your oil ages and is exposed to air, light and heat, its smoke point will decrease.
Do you know your oil’s smoke point?
Pick your oil based on the cooking method you want to use. If you go past the smoke point and your oil starts to burn, turn off the heat immediately and turn on a fan or open a window to ventilate any toxic smoke and fumes. Eating burnt oil is super unhealthy. Even though it’s sad to ruin a good meal (and no matter how wasteful it feels), it’s time to start your meal over again.
After your oil has cooled down completely, you can still dispose of your meal in an environmentally friendly way:
- Dispose of vegetables or fruits in your compost or green waste bin;
- Dispose of animal products (including meat, bones, butter, milk or fish skins) in your green waste bin; and
- Soak a paper towel with the cooking oil and either freeze it or let it harden naturally, and then dispose of it in your green waste bin.
Never pour used cooking oil down the sink, drain or toilet. It can clog the drain pipes in your home and neighbourhood, and cause your sewer system to back up.
Air, heat and light can create free radicals that degrade oil’s taste and quality. Store your oil in an airtight bottle in a cool, dark spot or the refrigerator to help extend its lifespan.
3. Select oils based on how they’re processed
Oils are made out of many different ingredients from fruits and vegetables, to animal products and fish. And their production methods can impact nutrient availability and fat composition.
When producing unrefined oils, plant materials are mechanically pressed and oil is extracted. Some oils are also lightly filtered to remove large particles. Unrefined oils are typically more nutritious and have stronger flavours, colours, and fragrances. They also have a shorter lifespan and lower smoke point that makes them better for no or low heat cooking. Many types of oils can be unrefined such as sesame, olive, avocado, and walnut oils.
How to identify unrefined oils: Check labels for terms like “unrefined,” “expeller pressed,” “cold-pressed,” “virgin” and “extra-virgin.” These oils tend to look cloudy and are packaged in dark bottles.
Oil refining usually involves treating plant materials with chemical solvents (like hexane) to release the fat. The oil is cleaned using high heat and then it is refined, bleached and deodorized (a process known as “RBD”). Oils can also be naturally refined using gentler methods like steam, filtering, and straining, but this is not the most common practice.
RBD oils can be less nutritious, and have lighter flavours, colours, and fragrances. The refining process gives the oil a longer shelf life and a higher smoke point that makes it better for high heat cooking. Manufacturers are also producing “high oleic” refined oils that are higher in oleic fatty acids (monounsaturated fats) and can be used for high-temperature cooking. Oils labeled “high oleic” can include safflower oil, sunflower oil, canola oil, algal oil, and peanut oil.
Small amounts of chemical solvents like hexane may remain in the oil after processing. Although the documented health effects of hexane (like dizziness, headache, numbness in the extremities, and blurred vision) focus on what happens if you breathe it directly, trace amounts of chemicals are definitely not an ingredient in my recipes! High heat processing can also reduce oil’s beneficial fatty acids and can create low levels of trans fat.
How to identify refined oils: Check labels for terms like “refined,” “hydrogenated,” “partially-hydrogenated,” and “cold-processed.” It’s safe to assume that any oils that don’t say “expeller pressed” or “cold-pressed” are industrially-refined. Refined oils tend to look clearer and be stored in clear bottles.
There are lots of other factors for picking the right oil including production practices. Stay tuned for future posts all about environmentally friendly oil production.
Choose less processed oils to eat a little greener
The less processed the better. Try to buy unrefined, expeller pressed, cold-pressed and organic oils (whenever possible) to get the maximum amount of nutrients and health benefits for your money. When it comes to price, you may find expeller pressed oils to be less expensive, and cold-pressed and organic oils at the more expensive end of the budget spectrum.
Not all countries regulate oil production process labelling (i.e. it is regulated in the European Union, but not in the United States). Confirm what is required on food labels with your food regulator, and read labels for certifications such as Ecocert and USDA Organic.
Compare oils to find the right one for you
The following table will help you compare culinary oils and decide which one’s are the best for you. It includes:
- The type of oil, from algae to animal.
- The smoke point, an approximate temperature when oil will start to burn.
- The highest heat level a cooking oil can be used for.
- Which cooking methods to use for each oil.
- The main fat type (highest amount) present in an oil.
Since some refined oils are processed using chemical treatments, and so we left them out of this table. Some oils are not refined using chemicals, but we suggest researching refined oils on a case-by-case basis before you buy. Note that some oils may have a high smoke point, but they’re not recommended for high heat cooking due to high levels of polyunsaturated fatty acid.
Thanks to Vectorpocket / Freepik for the vegetable, nut and fruit graphics used in the table above.
Conclusion: Our recommended culinary oils
There’s a huge range of oils to pick from, so here are some recommendations for oils that we keep in our cupboards.
For searing meats or roasting vegetables, choose fats that can take the heat. Ghee (clarified butter) is a good choice that’s high in saturated fats, and naturally refined avocado oil has a high smoke point.
Medium-high to medium heat
Your oil choices for stir-frying, pan frying, and baking really start to open up. Fruit and nut oils like virgin avocado, expeller pressed canola/rapeseed, and cold-pressed hazelnut oil can add nutrients and flavor. Animal fats like lard or bacon, duck, goose and chicken fat are great too and have high levels of monounsaturated fats that resist oxidation.
Not all oils are suitable for deep frying, especially oils with a smoke point below 390˚F (200˚C). To be on the safe side, use animal fats like beef and lamb tallow or suet, or mustard seed oil.
Low-medium to low heat
Use flavourful and fragrant oils for slower and gentler cooking. Pick up some cold-pressed or expeller pressed red palm, sesame, olive, and coconut oils to add depth to your baking, sautéing, stewing, and pressure cooking.
Many nut, seed, and vegetable oils are unstable at high heat due to their high polyunsaturated fat content. But these oils are nutrient powerhouses when eaten raw! Up your omega-3 intake by using flaxseed/linseed and walnut oil to dress a salad or drizzle as a finishing oil.
Fats are incredibly important for our brains and bodies. And oils are one delicious way to get the essential fatty acids we need. They’re also a great opportunity to make small changes for a healthier you and a greener planet.