The Chemistry of Cooking Fats: Stability, Inflammation, and Health

Author: Rohan Smith | Functional Medicine Practitioner | Adelaide, SA

In the functional medicine community of Adelaide, “clean eating” is a common focus, yet the foundation of those meals—the cooking fat—is often overlooked. The wrong oil, particularly when heated, can transform an otherwise healthy meal into a source of oxidative stress and inflammation. At Elemental Health and Nutrition, clinical assessment frequently reveals that fat quality plays a meaningful role in gut inflammation and microbiome disruption, especially in patients with chronic inflammatory conditions.

Quick Answer: What Is the Best Oil for Cooking?

The best cooking oils are those with high oxidative stability, not simply a high smoke point. Smoke point describes when an oil begins to burn, whereas oxidative stability reflects how resistant an oil is to heat-induced breakdown into harmful polar compounds. Fats rich in saturated or monounsaturated fatty acids—such as ghee, tallow, and extra virgin olive oil (EVOO)—are among the most heat-stable options for everyday cooking.

The Science: Why Fat Structure Matters

The health effects of cooking fats are best understood by examining their molecular structure, particularly the presence or absence of double bonds.

  • Saturated fats (butter, ghee, tallow, coconut oil) contain no double bonds, making them highly resistant to heat and oxidation.
  • Monounsaturated fats (olive oil, macadamia oil, avocado oil) contain one double bond and demonstrate good heat stability, especially when accompanied by natural antioxidants.
  • Polyunsaturated fats (seed oils such as canola, sunflower, and corn oil) contain multiple double bonds, which are vulnerable sites for oxidative damage during heating.

The Smoke Point Myth vs Oxidative Stability

While smoke point is often promoted as the key indicator of a “safe” cooking oil, research shows that refined oils with high smoke points can generate greater quantities of toxic polar compounds when heated. In contrast, less refined oils such as extra virgin olive oil may remain more stable during typical home cooking due to their antioxidant content.

Fat / OilOxidative StabilityPrimary UseClinical Consideration
Ghee (grass-fed)Very highHigh-heat cookingHeat-stable fat with milk solids removed.
Extra virgin olive oilHighGeneral cookingPolyphenols help protect against oxidation.
Avocado oilModerate–highHigher-heat cookingStability depends on being cold-pressed and unrefined.
Tallow (beef fat)Very highFrying and roastingNaturally low in polyunsaturated fats.
Seed oils (canola, sunflower)LowAvoid high heatProne to oxidation due to high omega-6 content.

Why Heated Seed Oils May Contribute to Inflammation

In clinical practice, diets high in repeatedly heated seed oils are commonly observed in individuals presenting with persistent fatigue, immune dysregulation, and metabolic stress. Oxidative by-products formed during heating can impair mitochondrial energy production, a pattern frequently seen in patients with chronic fatigue and post-viral illness.

Excessive dietary omega-6 linoleic acid may also incorporate into cell membranes, increasing susceptibility to inflammatory signaling pathways associated with immune dysregulation.

Sourcing High-Quality Cooking Fats in Adelaide

South Australia produces some of the world’s highest-quality extra virgin olive oils. When selecting cooking fats:

  • Check for a listed harvest date to ensure freshness.
  • Choose oils packaged in dark glass to reduce light exposure and oxidation.
  • Source animal fats from pasture-raised South Australian producers when possible.

Frequently Asked Questions

Can I cook with extra virgin olive oil?

Yes. Despite a moderate smoke point, extra virgin olive oil demonstrates good stability during typical home cooking temperatures due to its antioxidant polyphenols.

Why is ghee often preferred over butter for cooking?

Ghee has the milk solids removed, improving heat stability and making it more suitable for individuals sensitive to lactose or casein.

How can I tell if an oil has gone rancid?

A rancid oil may smell stale, paint-like, or fishy. These odors indicate lipid peroxidation and oxidative degradation.

Key Insights

  • Oxidative stability is more important than smoke point when choosing cooking oils.
  • Saturated and monounsaturated fats tolerate heat better than polyunsaturated oils.
  • Repeated heating of seed oils may contribute to inflammatory burden.
  • High-quality extra virgin olive oil is a practical, everyday cooking fat.

Optimise Your Kitchen Pharmacy

The fats used daily play a meaningful role in inflammation, metabolic health, and cognitive clarity. For individuals experiencing chronic fatigue, brain fog, or inflammatory symptoms, reviewing dietary fat intake can be an important step. Personalised nutrition strategies and functional testing can be explored through a consultation at Elemental Health and Nutrition or by reviewing available clinical services via the testing and programs portal.

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