What Fats/Oils are Best for High Heat Cooking?
In my most recent blog post I tackled the question “Are Seed Oils Really that Bad?” (I recommend giving it a quick read before continue on). I received a great follow-up question from Katie: “For high heat cooking, it is recommended to use oils with higher smoke points like refined avocado or refined olive oil. But I’ve also heard refined oils aren’t as good for you either? Not sure which to choose – unrefined and deal with smoking oil, or refined? Thanks!”
I’ll be honest, there’s a lot of conflicting information out there regarding which oils to use for cooking, especially high heat cooking. To make an educated decision on where and when to use which types of oils/fats in cooking we need to understand how fats are classified, what refined vs unrefined means, and what happens to these fats when heated.
A Mini Lesson on Fats
All fatty acids are essentially long chains of carbon atoms with hydrogen atoms filling the available bonds. The types of bonds determines the type of fat. There are two types of fats, saturated and unsaturated.
Saturated fatty acids have single bonds where all the carbon atom linkages are filled or “saturated” with hydrogen. They are straight in form and pack together tightly so they tend to be solid or semi-solid at room temperature. Because of their saturation they are highly stable and do not normally go rancid, even when heated. Saturated fats are found mostly in animal fats, dairy (whole milk, cream, butter, cheese), and tropical oils (coconut and palm oil).
Unsaturated fatty acids have one or more double bonds between the carbon atoms. These double bonds produce a bent shape which prevents the molecules from packing together. They remain loosely packed and tend to be liquid at room temperature, some are even liquid when refrigerated. Unsaturated bonds are unstable to heat and light and can become damaged. Unsaturated fats can be further broken down into monounsaturated fats or MUFAs (one double bond) and polyunsaturated fats or PUFAs (two or more double bonds). Unsaturated fatty acids are found mostly in avocados, olive oil, nuts, seeds, and fish.
All fat-containing foods have more than one type of fat, but generally one type will be more prominent than others. For example we classify olive oil as a monounsaturated fat because its typical fatty acid composition is 14% saturated fat, 77% monounsaturated fat, and 9% polyunsaturated fat.
Cooking with Fats
When assessing a fat or oil’s ability to withstand heat we want to look at the prominent type of fat, the smoke point, whether it is refined or unrefined, and the fat’s oxidative stability.
Smoke point is the temperature at which the fats begin to break down and turn into smoke. If you go far above an oil’s smoke point you can reach the flash point where it bursts into flames. The smoke point of an oil depends on the type of fat as well as whether they are refined or unrefined.
Type of Fat: The more double bonds a fat has the more prone it is to oxidation and damage from heat and light exposure. PUFAs and MUFAs are the most unstable and prone to damage. This damage can come from the processes used to extract oil from vegetables/seeds (mechanical, heat, and chemical) as well as from heating the oil during cooking.
- Saturated fats (beef fat, butter fat, coconut, palm oil) have higher smoke points.
- Monounsaturated fats (avocado, olive) have medium smoke points.
- Polyunsaturated fats (sunflower, flaxseed, safflower) tend to have a lower smoke point.
Refining helps removes impurities, free fatty acids, vitamins and antioxidants that can start to burn and give off smoke. Because refined oils are lower in nutrients and free fatty acids which can burn they tend to have a higher smoke point. (Interesting fact: as an oil is heated, more free fatty acids are produced, which lowers the smoke point. These free fatty acids can be oxidized and form free radicals. This is part of the problem with eating fried restaurant foods where the fryer oil is heated for extended periods of time and reheated and reused.)
Oxidative Stability looks at how resistant the fats are to reacting with oxygen. What helps reduce oxidation and damage? Antioxidants! Fats such as unrefined 100% extra virgin olive oil have high levels of polyphenols (antioxidants). Oils with higher levels of polyphenols produce fewer oxidative by-products when heated because these antioxidants protect the oil from breaking down during heating (DeAlzaa, Guillaume, & Ravetti, 2018).
The Over-Reliance on Smoke Point and Dismissal of Protective Polyphenols
Historically there has been an over reliance on smoke point when assessing a cooking oil. Smoke point is a crude measure of an oil when it starts to have visible smoke, and an oils smoke point depends on many factors such as the moisture, acidity, and antioxidant properties of an oil (Del Coro, 2022).
We’ve been told to use refined oils because it was believed that the high heat would just destroy most of what makes oils like extra virgin olive oil and unrefined avocado oil healthy (free-radical fighting polyphenols) when the opposite is actually true. The high levels of antioxidants can protect the oil from forming various harmful compounds when heated and a significant amount will still remain in the oil after heating (Li et al., 2016). Research has also found that vegetables fried or sautéed in olive oil contain higher levels of antioxidants due to the polyphenols that were transferred from the oil into the food during cooking (Ramírez-Anaya, Samaniego-Sánchez, Castañeda-Saucedo, Villalón-Mir, & de la Serrana, 2015).
Putting it All Together – What Oils Do I Recommend?
Due to the unstable nature of unsaturated fats (PUFAs and MUFAs) it is probably not best to use liquid fats (oils) for high temperature cooking, except for special dishes. Saturated fats are stable at high heat and they are what I most often use and recommend for sautéing, frying, and pan searing. I often use grass fed beef tallow (I love Epic Beef Tallow), or grass fed butter and ghee. When I do use liquid oils for sautéing and pan frying I rely on 100% unrefined extra virgin olive oil and unrefined cold pressed avocado oil. I try to mix up the fats I use so I get a nice balance of fatty acids and polyphenols. For example I often use tallow when making eggs or pan searing steaks or cooking hamburgers on my stovetop. When I make my homemade gluten free chicken tenders I use avocado oil to fry them. When I sauté veggies I use either extra virgin olive oil or butter depending on the flavor profile I am looking for. When I bake I use butter, non-hydrogenated palm oil, or coconut oil.
Navigating all of the food and nutrition information out there is tough. Many of my clients have come to me because they want expert guidance – they are finding conflicting information online and they don’t know what to believe. I love to sort through the science and help people make informed decisions that will support their unique health and wellness goals. If you are struggling with fatigue, anxiety, weight gain/weight loss resistance, and hormonal imbalances and feel like you have tried all the things I would love to chat with you. Call or e-mail me to schedule your complimentary Nourish to Flourish Strategy Session to get started on your path to wellness.
Amanda Watson, BCHN®
De Alzaa F., Guillaume C, Ravettie L. (2018). Evaluation of chemical and physical changes in different commercial oils during heating. ACTA Scientific Nutritional Health 2.6 (2018): 02-11. Retrieved from https://www.actascientific.com/ASNH/pdf/ASNH-02-0083.pdf
Del Coro, K. (2022, August 21). Yes, you can cook with olive oil over high heat – here’s why. Retrieved from https: https://www.realsimple.com/food-recipes/cooking-tips-techniques/olive-oil-smoke-point-myth#:~:text=Even%20when%20heated%20past%20its,even%20more%20remain%20after%20heating.
Gunnars, K. (2018, November 23). Is olive oil a good cooking oil? A critical look. Retrieved from https://www.healthline.com/nutrition/is-olive-oil-good-for-cooking?fbclid=IwAR1infqoxW86ywXGX8rwlulJsZAYspevYnB2Y9a62-volokcH3j8Bu7njqc
Li, X., Bremer, G., Connell, K., Ngai, C., Pham, Q., Wang, S., Flynn, M., Ravetti, L., Guillaume, C., Wang, Y., & Wang, S. (2016). Changes in Chemical Compositions of Olive Oil under Different Heating Temperatures Similar to Home Cooking. Journal of Food Chemistry and Nutrition, 4(1), 07-15. doi:https://doi.org/10.33687/jfcn.004.01.1532
Ramírez-Anaya, J.delP., Samaniego-Sánchez, C., Castañeda-Saucedo, M. C., Villalón-Mir, M., & de la Serrana, H. L. (2015). Phenols and the antioxidant capacity of Mediterranean vegetables prepared with extra virgin olive oil using different domestic cooking techniques. Food chemistry, 188, 430–438. https://doi.org/10.1016/j.foodchem.2015.04.124