Fats are essential to health. They are required for proper cell function, production of hormones, healthy stress response, immunity, detoxification, smooth digestion, and fat soluble vitamins A, D, E and K. Around 60% of the brain consists of fat. Before the industrial food processing methods and cheeky marketing practices, picking fats for the kitchen was a no-brainer. Nowadays, it’s almost a job for a scientist.
Trust biochemistry, not marketing
You can scroll down till the end and see how to use your fats wisely but that it not the point of this post. Don’t skip this technical (and perhaps boring) paragraph because it will help you make informed decisions, regardless of what you’re being told. Health starts with knowledge!
People always ask me what fats are ok for cooking. And so the fun beings. There are two main factors to consider:
Oxidation (in)stability - determined by the absence or presence of double bonds in molecules of a given fat; the main criteria to determine if a fat is suitable for cooking
Smoke point - the temperature at which visible smoke is produced when a fat is heated
In chemistry, double bonds between atoms are much weaker than single bonds and therefore are site of potential damage called oxidation. In other words, the more double bonds in a fat, the more damaged (oxidised) it can become. In the world of nutrition, oxidised fats should be avoided due to their inflammatory and ageing properties.
If a new fancy fat appears on the market and you’re unsure about the marketing claims, check how many double bonds it contains. If more than one, then should not be used for cooking.
Saturated vs unsaturated
Saturated fats have no double bonds because each carbon atom is saturated with hydrogen, making it resistant to damage. Examples: coconut oil, palm oil, animal fats.
Unsaturated fats: contain double bonds because some atoms of carbon are not saturated with hydrogen so are prone to damage. These are further divided into:
Monounsaturated fats have one double bond, meaning there is only one place of potential damage. Examples: olive oil, avocado oil (sources of omega 9).
Polyunsaturated fats have multiple double bonds so are much more prone to damage and should not be heated. They include omega 3 and omega 6. Examples: nuts, seeds, their oils, grains and supplemental oils like fish oil, cod liver oil, evening primrose oil, etc.
How does ‘smoke point’ come to this?
What really burns and produces the smoke is not the fat itself but various ‘impurities’ present in virgin fats - such as proteins, plant matter, even antioxidants (antioxidants can turn into pro-oxidants once exposed to a higher temperature). You probably noticed that virgin fats, including unrefined lard, have a stronger colour and smell - that is thanks to the ‘extras’ that can create smoke.
People learned how to bypass this by refining fats so that they become pure. Some oils are ok to be refined because less aggressive methods can be employed, such as those practiced with coconut oil, olive oil or clarifying butter. Unfortunately, seed oils cannot be refined in rather traditional ways and rely on aggressive industrial refinement, which is a toxic process. And for this reason alone, you should NOT CONSUME SEED OILS THAT ARE INDUSTRIALLY REFINED.
Seed oils that have a high smoke point through refinement (such as sunflower and rapeseed oils, marketed as health oils that are great for cooking) are still easily oxidised because they have multiple double bonds. I will repeat that double bonds is where most oxidation happens. In other words, refining of oil to raise its smoke point does not change the number of bonds between carbon atoms. There will be no smoke when exposed to a higher temperature but the fat itself will be toxic.
Fats suitable for cooking - resistant to oxidation
Clarified butter and ghee
Butter: ok for baking or cooking eggs; enjoy melted over cooked vegetables
Extra virgin olive oil: good for pasta sauces or gentle sauteeing. Once liquid or steam are present, that will protect the fragile polyphenpls from burning
Refined olive oil: good for higher temperatures
Refined coconut oil with an added bonus of a neutral taste. It should be mechanically or steam refined, like this one or this one
Animal fats: duck and goose fat, lard, beef tallow, drippings
Fats for cold use - prone to oxidation
Rich in polyphenols which act as antioxidants so it’s important to treat them with care - keep away from excess light and heat. Some of these are polyunsaturated fats and for that reason alone should not be heated.
Extra virgin (cold pressed) olive oil: use in salad dressings or over cooked vegetables
Extra virgin, cold pressed coconut oil: use in smoothies, energy balls, bulletproof coffee, green tea, or for therapeutic purposes (off the spoon as appetite suppressant, topically for sun burns and anti-fungal properties)
Flax oil: use in salad dressings, smoothies or take it off the spoon as a supplement; keep in a dark bottle in the fridge (polyunsaturated)
All other nut and seed oils like sunflower seed, rapeseed, sesame, peanut, hemp, milk thistle or black seed. They should always be cold pressed and kept in the fridge (polyunsaturated)
Fats to avoid
Commercial sunflower seed and rapeseed oils (non-cold pressed, sold in most shops and marketed as suitable for cooking)
Corn and vegetable oils
Liquid coconut oil
Artificial trans fats and all foods that contain them: margarine, vegetable shortening, frozen pizza, shop bought baked foods like croissants and doughnuts and cookies, refrigerated or frozen dough (puff pastry, shortcrust, rolls)
You probably wonder why we are told to cook with rapeseed or sunflower oil. And rightly so! First of all, these are GMO which makes them grow easily as they are engineered to resist herbicides and pesticides (aka easy profit). Secondly, when these are refined, the taste is rather neutral and they don’t smoke in a high temperature- a very tempting aspect for anyone who cooks. Since people are not able to raise the smoke point at home without industrial equipment, it makes one depend on the industry, again - generating profit. Last but not least, these are a source of omega 3 and 6 which are such hype words. But omega 3 and 6 fatty acids should ever be heated, even when refined. The bottles or rapeseed oil should really say ‘a source of oxidised and inflammatory omega 3’.
Is palm oil unhealthy? NO. The only problem with palm oil is the deforestation of the Amazon and similar areas, making it an unethical choice for many. Otherwise, palm oil is a beautiful, healthy oil that has been used traditionally in the tropics for a long time - just like coconut oil.
Can you cook with olive oil?
Summary
Your health should always dictate which fats are the best to use and in what combination with other foods. For example, coconut oil may be great but can contribute to acne in some individuals.
Culinary fats should complement rather than substitute each other and if possible, it’s good to have a variety and use them in different ways. For example, I scramble eggs and make Indian curries with ghee, cook Thai curries with coconut oil, use olive oil in salad dressings, drizzle stir fries with sesame oil and make potato fries with lard or duck fat.
In the previous post I discussed how to take the most common supplements including supplemental oils, in order to get most benefits.