Alternative Health

Cooking Oils: What to Use & Avoid

The oil you cook with matters more than most people realize. Heat degrades oils at different rates depending on their fatty acid profile, and degraded oils produce compounds you do not want to eat. The key variables are smoke point, oxidation stability, and fatty acid composition.

Smoke Points

The smoke point is the temperature at which an oil begins to break down, producing visible smoke and harmful aldehydes. Cooking above an oil's smoke point generates acrolein, HNE (4-hydroxynonenal), and other toxic byproducts.

Avocado oil (refined): ~520F / 271C

Highest smoke point of common cooking oils. 70% monounsaturated fat. Best all-purpose high-heat oil. Caveat: widespread adulteration. UC Davis study found 82% of avocado oils tested were rancid or adulterated with cheaper oils. Buy from verified brands.

Extra virgin olive oil: ~375-410F / 190-210C

Despite its moderate smoke point, EVOO produces fewer harmful compounds when heated than oils with higher smoke points. Polyphenols and antioxidants protect against oxidation. Australian research found EVOO was the most stable oil across all cooking temperatures. Safe for sauteing and moderate-heat cooking.

Coconut oil (refined): ~350F / 177C

92% saturated fat makes it extremely stable against oxidation. Medium-chain triglycerides (MCTs, primarily lauric acid) metabolize differently than long-chain fats. Good for baking and medium-heat cooking. Virgin coconut oil has a lower smoke point (~350F) but more polyphenols.

Butter / ghee: ~350F / 177C (butter), ~485F / 252C (ghee)

Butter contains milk solids that burn at ~350F. Ghee (clarified butter) removes milk solids, raising the smoke point significantly. Grass-fed butter/ghee contains more K2 and CLA. Ghee is excellent for high-heat cooking.

Oxidation Stability

Smoke point alone is misleading. Oxidation stability is what actually determines how much harmful chemistry happens during cooking. The hierarchy:

Saturated fats (coconut, tallow, butter) are most stable because they have no double bonds to oxidize. Monounsaturated fats (olive, avocado) have one double bond and are moderately stable. Polyunsaturated fats (seed oils, fish oil) have multiple double bonds and oxidize rapidly with heat, producing the most aldehydes.

This is why a polyunsaturated oil can have a high smoke point but still produce significant toxic byproducts during cooking. Smoke point and oxidation stability are different measurements.

Omega-6:3 Ratios

Ancestral diets had an omega-6 to omega-3 ratio of approximately 1:1 to 4:1. Modern Western diets average 15:1 to 20:1, driven largely by seed oil consumption. Excess omega-6 (linoleic acid) is pro-inflammatory when it dominates the ratio.

  • Soybean oil: 7:1 omega-6:3
  • Corn oil: 46:1
  • Sunflower oil (high-linoleic): 200:1+
  • Canola oil: 2:1 (lowest ratio of seed oils)
  • Olive oil: 13:1 (but total PUFA is very low, so absolute amounts are small)

The Seed Oil Debate

The anti-seed-oil position: industrial seed oils (soybean, corn, canola, sunflower, safflower, cottonseed) are a post-1900 invention, consumed in amounts our biology never adapted to. Linoleic acid intake has increased from ~2% to ~8% of calories. This correlates with rising rates of obesity, heart disease, and inflammatory conditions.

The mainstream position: randomized controlled trials replacing saturated fat with vegetable oils show reduced LDL cholesterol. The AHA recommends polyunsaturated oils. Correlation with disease trends does not prove causation.

What the evidence suggests: linoleic acid accumulates in body fat and cell membranes over months. Its oxidation products (OXLAMs) are biologically active and pro-inflammatory. Whether this matters clinically at current consumption levels is genuinely debated. Reducing seed oil intake while increasing olive oil, butter, and animal fats is a reasonable precautionary approach.

What to Use at Each Temperature

  • No heat (dressings, finishing): extra virgin olive oil, flaxseed oil, walnut oil
  • Low-medium heat (sauteing, eggs): butter, EVOO, coconut oil
  • Medium-high heat (stir fry, pan searing): ghee, avocado oil, tallow
  • High heat (deep frying, if you must): tallow, lard, refined avocado oil