7 worst cooking oils that harm your health

May 2, 2025 ET Online

Partially Hydrogenated Vegetable Oil

Used in processed foods, this oil contains trans fats that raise bad cholesterol, lower good cholesterol, and increase heart disease risk. Even small amounts can be extremely damaging over time. Image Source: iStock

Corn Oil

Though marketed as heart-healthy, corn oil is extremely high in omega-6 fats, which can trigger chronic inflammation, obesity, and heart issues when consumed in disproportionate to omega-3s. Image Source: iStock

Sunflower Oil (Refined/High-Heat Use)

Refined sunflower oil is unstable under high heat, producing toxic aldehydes. Though often considered heart-healthy, its high omega-6 content and low heat stability make it risky when frying. Image Source: iStock

Canola Oil (Refined/Low-Quality)

Refined canola oil undergoes high-heat processing and chemical treatment, often producing trace trans fats and oxidised compounds that contribute to inflammation, arterial damage, and poor cardiovascular health. Image Source: iStock

Cottonseed Oil

Extracted from a non-food crop, cottonseed oil often contains pesticide residues and is extremely high in inflammatory omega-6 fats, making it a poor choice for regular cooking. Image Source: iStock

Palm Oil (Refined)

While unrefined red palm oil has some benefits, the refined version is often processed at high heat, which damages nutrients and creates harmful oxidation by-products during cooking. Image Source: iStock

Grapeseed Oil

Often marketed as healthy, grapeseed oil is unstable at high temperatures and high in omega-6s. It oxidises easily, forming compounds that may harm cells and promote inflammation. Image Source: iStock

Next: 10 motivational quotes to push athletes beyond their limits

Thanks For Reading! Read Next