The ‘healthy oil’ myth: Why refined vegetable oils may be slowing your metabolism

Furthermore, the heating of oils, particularly the refined ones, results in the formation of trans fats and lipid oxidised products, which are a major health concern.

How refined oils impact your health

Refined vegetable oils have been subjected to high-temperature processing, chemical solvent extraction, bleaching and deodorising to remove impurities but also to eliminate all beneficial micronutrients. Moreover, the repeated heating of refined oils during cooking leads to the generation of trans fats and lipid oxidation products.

The consumption of refined sunflower and soybean oils can lead to an increased intake of omega-6 fatty acids, which can result in an improper omega-6 to omega-3 ratio in the body. Such a situation is linked with insulin resistance, higher triglycerides and elevated LDL cholesterol levels. Chronic biochemical stress from these imbalances could deteriorate blood sugar control and lipid profiles over time, even with an apparently “moderate” total food energy intake.

Why pure oils behave differently

Pure, unrefined oils are generally better because they retain natural nutrients, antioxidants, vitamins (like E & K), and healthy fatty acids (Omega-3s) from the source, offering more health benefits, distinct flavour and a lower risk of harmful trans fats. Mustard oil contains alpha-linolenic acid and allyl isothiocyanate, which are omega-3 fat and a compound that support lipid metabolism and insulin sensitivity respectively. Sesame oil is a source of potent antioxidants, sesamol and sesami, whose effects on cholesterol ratios are positive. Extra virgin olive oil is, without a doubt, the healthiest oil as it is rich in both monounsaturated fatty acids and antioxidants.

While these oils do not reduce fats, they, however, are supportive of fat metabolism. Their anti-inflammatory properties and ability to create the right hormonal environment add up to benefits.

No calorie counting; no crazy restrictions — just a change in quality of fat.

Why oil quality matters more than oil quantity

It is not fat that poses the problem, it is dysfunctional fat. Refined oils, regarded as heart-healthy, might still be the overload as they lack protective compounds. The use of pure oils in moderation results in improved nutrient absorption, blood sugar stabilisation and hormonal balance.

This does not mean using large volumes of any oil. Portion control is still something that needs to be practised. But while that is so, selecting oils that work along with your metabolism and not against it has a major bearing on the health outcomes in the long run.

Rethinking Indian cooking traditions was never wrong; they were only waiting for a comeback. The shift toward refined oils was driven by industrial convenience, not nutritional wisdom. As lifestyle diseases mount, returning to minimally processed, regionally appropriate oils is not nostalgia, it’s evidence-based self-care. The question to ask is whether this oil will nourish or stress my body. When that lens changes, so does one’s health, sometimes with more power than any diet trend.

(Kathuria is a clinical dietician)