skip to Main Content

Can You Really Cook with Olive Oil?

The short answer is yes. Of course you can. Trouble is, the Canola and Soy oil industry are threatened by olive oil, and want us to ignore olive oil’s multi-thousand year track record of serving as a delicious and life giving food for the Romans, the Greeks, the Albanian–and the rest of the Mediterranean. So the edible oil barons had to get creative to convince consumers to mistrust culinary history and tradition as ample evidence of safety.

What did they come up with?

“The edible oil industry cooked up a scary sounding problem: smoke point.”

You’ve probably heard the term “smoke point” and probably correctly guessed what smoke point means. The smoke point is the point at which an oil literally ignites and burns, creating a visible wisp of blueish smoke. The RBD (Refined Bleached Deodorized) seed oil industry makes the claim their products are better to cook with because they have a “better” (higher) smoke point–meaning that their products have a better ability to tolerate higher temperatures without literally smoking.

The smoke point of an oil is believed to be correlated with the safety and stability under heat, although technical evidence to support this is limited

Authors of the 2019 article “Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating”

We’ve probably all had our moments in the kitchen when we forgot something on the stove, and the whole pan started smoking–the food, the oil, who could tell?–but I don’t think anyone seriously expects that an oil be flame proof just to be able to cook with it

Image result for kitchen on fire cartoon

Still, to a chef, or a household cook, smoke point may sound like a reasonable concern. To an organic chemist, however, the claim that smoke point is in any way relevant smells like a propaganda campaign.

Firstly, most food contain enough water that it will start to sizzle around 212 degrees F, the boiling point of water, which is well below the smoke point of any oil. That sound is a warning that it’s time to stir or flip or turn down the heat, and it’s a far better indicator than the smoke rising from the pan or fire alarms going off.

“Focusing on smoke point draws our attention away from what really matters about cooking oils: their ability to endure heat”

Smoke point is actually a very unhealthy idea for two reasons. First, it’s been so effectively used to sell cheap, less nutritious cooking fats that these flavorless factory foods (that meet every definition of junk food) have now largely replaced olive oil in restaurants, even in pizza joints and fine Italian eateries. Second, smoke point draws our attention from the real point of chemistry that impacts human health, and that has to do with it’s polyunsaturated fatty acid (PUFA) content. (#vegoilsucks)

The edible oil industry has so effectively drilled home this false idea that for an oil to be suitable for cooking it needs to have a high smoke point that it is now very tough to convince chefs otherwise. Unfortunately, even if an oil has a high smoke point, the PUFA fats in the oil, which are present in abundance in canola, corn, soy and other so called ‘vegetable oils’ are invisibly breaking down in a harmful way long before they start smoking.

Imagine what would happen to a glass hit by a mallet; it would explode into a thousand shards. That’s what happens to PUFA fats when they’re heated. Now imagine a sheet of metal hit by a mallet. The mallet bounces right off and the metal sheet is unchanged. That’s what happens to saturated fats when they’re heated. Butter, coconut oil and olive oil are high enough in saturated fat that they do not break down under normal stovetop cooking conditions.

It’s the PUFA content of the oil, not the smoke point, that most powerfully determines how well a given oil tolerates heat and therefore whether the food you cook in it will be healthy and delicious. Long before an oil smokes, it breaks down in a way that’s invisible to the eye and toxic to our cells. The higher an oils PUFA content, the faster it breaks down. This occurs because the double bonds in PUFAs are highly reactive with oxygen.

(Deep frying and especially repeated use deep frying is another animal that deserves its own article. While olive oil still does better than the high PUFA seed oils in deep fryers, no oils stands up for a week–which is how long many restaurants go without changing their oil. Ick.)

Whenever polyunsaturated oils are heated, and long before they start to smoke, they start to oxidize, meaning oxygen breaks individual molecules apart, into smaller molecules. The end product of the broken down PUFA fats are highly toxic, new compounds that don’t normally exist in nature in any significant quantity and that our bodies cells can’t handle.

We can see and understand smoke. But the concept of molecular deterioration is too abstract, and we can only measure it with sophisticated lab equipment. Until recently, nobody had actually run a comprehensive comparison of high smoke point, high PUFA oils to olive oil. And they found exactly what any serious student of organic chemistry could have predicted: That high PUFA Canola, grapeseed and rice bran produce a ton of break down products called polar compounds. See below, from “Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating”

What we see is how well the 10 different oils stand up to heat. As the temperature increases above 150 degrees C, there is a rapid rise in polar compounds. Polar compounds are bad for our health. So bad that when present above 25% an oil is considered unfit for human consumption. The highest concentration of polar compounds was found in Canola oil, at 27.5%, followed by grapeseed (19.3%) and rice bran (13.0%) oils.

You might think from looking at this one graph that this is the whole story of which oils are best. And if you’re a fan of sunflower oil, you might be mislead into thinking that sunflower oil performs better than one of the lower grades of olive oil. But polar compounds are only one category of PUFA break down products; there are many others and taken as a whole even the lower grades of olive oil outperform sunflower. If you’re interested, the full text with figures are available from ASNH (Acta Scientific Nutritional Health)

Finally, I’ll give the last word to one of my favorite chefs. Debby Lee who caters out of her company She started her own health journey after reading my second book, Food Rules: A Doctor’s Guide to Healthy Eating and eliminated the seed oils forever after.

Debby was glad to say goodbye to the high-smoke-point concept because “As a chef taste is always the most important thing. In using the high smoke point RBD oils, there is a definite wax like aftertaste on the food. So now, when I fry foods, I always veer to natural animal fat or avocado oil if a client is vegetarian.”

To hear a fun and informative podcast on the topic of olive oil, from one of the worlds leading authorities on what it takes to give olive oil the best flavor, check out this interview from Ben Greenfield:

Dr. Cate

With over two decades of clinical experience and expertise in genetic and biochemical research, Dr. Cate can help you to reverse metabolic disease and reshape your body.

Back To Top