A Practical Guide to Healthy Cooking Fats

The smoke point of an oil is the temperature at which it begins to visibly smoke and break down. Above the smoke point, oils decompose into free fatty acids, glycerol, and various oxidation byproducts — some of which (including acrolein and aldehydes) are harmful if consumed regularly in significant amounts.

However, smoke point is not the only relevant variable. Refined oils have higher smoke points but are more processed and contain fewer beneficial compounds. The oxidative stability of an oil (how well it resists chemical breakdown under heat) is equally important and is determined by its fatty acid composition — specifically, how saturated or unsaturated the fats are.

Highly saturated fats (coconut oil, butter, ghee, animal fats) are more heat-stable because saturated carbon bonds are harder to break. Monounsaturated fats (olive oil, avocado oil) are moderately stable. Polyunsaturated fats (most seed oils) are the least stable under heat.

A common myth is that extra virgin olive oil (EVOO) cannot be used for cooking and should only be used cold. Research from the University of the Basque Country found that EVOO is the most oxidation-resistant cooking oil tested, outperforming most seed oils even at high temperatures, due to its high monounsaturated fat content and natural antioxidants (polyphenols, vitamin E, squalene).

EVOO has a smoke point of approximately 190–210°C for high-quality versions — sufficient for sautéing, roasting at standard temperatures (180–200°C), and most everyday cooking. Its smoke point and oxidative stability are significantly better than most seed oils marketed for their higher smoke points.

Quality matters enormously. Look for: 'extra virgin' certification (not just 'olive oil' or 'light olive oil'), a harvest date (not just a best-before date) within the past 12–18 months, dark packaging, and a peppery/bitter taste (indicates polyphenol content). Oils that taste bland or buttery may be old, refined, or blended.

For high-heat cooking above 220°C (deep frying, very high-heat searing): refined avocado oil or ghee are well-suited. Both have smoke points above 250°C and good oxidative stability.

For everyday sautéing, roasting, and stir-frying (160–210°C): extra virgin olive oil is ideal — both for its stability and its flavour. Butter provides flavour but browns and burns at relatively low temperatures; combining butter with a small amount of olive oil raises the smoke point of the mixture.

For cold applications — salad dressings, drizzling on finished dishes, dips: use high-quality EVOO or oils you enjoy for flavour (sesame oil for Asian dishes, walnut oil, flaxseed oil). These oils provide the most flavour and nutritional benefit when not subjected to heat.

• Everyday cooking (sauté, roast): extra virgin olive oil
• High heat (deep fry, wok): refined avocado oil, ghee
• Flavour drizzle: quality EVOO, sesame, walnut
• Baking (neutral flavour needed): refined coconut oil, avocado oil
• Avoid for cooking: soybean oil, corn oil, sunflower oil, generic 'vegetable oil'

Refined seed oils — corn oil, generic vegetable oil, soybean oil, sunflower oil — are high in omega-6 polyunsaturated fats and have poor oxidative stability under heat. While these oils are not inherently toxic, their widespread use in high-heat cooking and ultra-processed foods has significantly increased the omega-6 to omega-3 ratio in Western diets, which is associated with increased systemic inflammation.

Partially hydrogenated oils (trans fats) should be avoided entirely. They are largely banned in many countries after conclusive evidence linking them to cardiovascular disease. Check ingredient lists for 'partially hydrogenated oil' in packaged foods, particularly older products and some imported goods.