Why olive oil is the best oil for frying

Contrary to popular belief, olive oil is one of the best oils for frying.  The medium-high smoke point of olive oil exceeds the temperatures needed for frying. Furthermore, olive oil contains oleic acid and minor compounds that protect the oil from breaking down, even after reuse. 

Frying is one of the most common and most delicious ways to prepare food. Throughout the Mediterranean, traditional foods like pescadillo, calamari, keftedes, patatas a la pobre, carciofi alla giudea, and falafel are all fried in olive oil.  Mediterraneans know that olive oil is the best oil for cooking and frying. So why do Americans believe that olive oil should only be used raw?

The science

Olive oil is one of the most stable oils for cooking. Unlike other common cooking oils, olive oil contains compounds and antioxidants that prevent the oil from breaking down under moderate heat.  Additionally, olive oil is mostly composed of oleic acid (Omega-9), a monounsaturated fatty acid that is naturally resistant to oxidation.

Multiple peer-reviewed studies have shown that olive oil is the best oil for frying.  Olive oil outperformed vegetable, peanut, corn, soybean, sunflower and canola oils.

• Olive oil can be heated to high temperatures - In 2013, Food Chemistry published a report comparing free radical formation and oxidation (rancidity) when heating peanut oil and extra virgin olive oil.  The researchers found that more heat was needed to start the oxidation process in the extra virgin olive oil than in the peanut oil. Read more 
• Olive oil can be reheated and reused safely - In 2014, the American Chemical Society's Journal of Agricultural and Food Chemistry published a study comparing refined olive oil with corn, soybean, and sunflower oils. They deep-fried and pan-fried potatoes at heat up to 374°F for up to ten successive sessions. Olive oil was found to be the most stable, had the greatest resistance to oxidative deterioration, and its trans-fatty acid contents and harmful compounds were found to be lowest.  Read more
• Olive oil can be heated to high temperatures for long periods of time - In 2012, Food Chemistry published a study comparing extra virgin olive oil to sunflower oil. Both oils were heated in an industrial fryer at 374°F for 40 hours. The study found that extra virgin olive oil performed better than sunflower oil. Read more
• Olive oil produces fewer harmful compounds when overheated - In 2004, a team studied the aldehydes produced by heating extra virgin olive oil, olive oil and canola oil to 464°F.  The study found that both extra virgin and regular olive oil were healthier than canola oil. Read more
• Olive oil is also good for shallow frying - A 2016 study experimented with shallow frying fish at 340°F in both extra virgin olive oil and sunflower oil. Olive oil performed better, showing more resistance to oxidation and degradation. Read more
• Frying in olive oil is heart healthier - Perhaps most interestingly, a study in the British Medical Journal states that there is no link between the consumption of fried foods and heart disease when the food was fried in olive oil. Read more 
• Frying in olive oil may fight disease - A 2016 study found that vegetables fried in extra virgin olive oil contained more phenols and antioxidants than vegetables boiled in water.  Read more.

More peer review studies can be found here and here.

Smoke point

Often, the smoke point of olive oil is cited as the reason why olive oil should not be heated or used for cooking.  However, a recent study found that smoke point is not a reliable indicator of a cooking oil's stability. Furthermore, the smoke point of olive oil is comparable, and in some cases higher than, common cooking oils such as soybean, sunflower, peanut, canola and corn oils. 

The International Olive Council (IOC), the authority on olive oil, recommends the following temperatures for frying in olive oil.

The smoke point of olive oils are above the temperatures needed for frying. The below chart shows the smoke points of olive oils and for reference, the smoke points of other oils commonly used for frying.  The smoke points are listed as ranges. The actual smoke point depends on the free fatty acid content and level of refinement. 

Tips for frying with olive oil

1. Regular olive oil and extra light tasting olive oil are the most cost efficient for frying. If cost is not a factor, consider using extra virgin olive oil.
2. Don't worry that your food will taste like olives. Heating olive oil will neutralize much of the flavor. 
3. Make sure that the oil is hot enough before adding the food (a thermometer is a good idea). Olive oil will help your food form a crust and will help prevent your food from absorbing too much oil.
4. Studies have shown that even as part of a Mediterranean diet, fried foods were associated with weight gain, so consume fried foods in moderation. Read more.

Resources

• Olive oil vs. corn, soybean and sunflower oil
• EVOO vs. sunflower oil
• EVOO and OO vs. canola oil
  
• Olive oil vs. sunflower oil
• Olive oil vs. peanut oil

Further Reading: 

• Smoke Point Is Not a Reliable Indicator of Cooking Oil Stability
• The Culinary Institute of America Clarifies Guidance on Cooking With Olive Oil
• Olive Oil Retains Health Benefits During Cooking
• USDA Recommends Olive Oil for Deep Frying 
• US News reports on olive oil smoke points