Certain seed oils are often considered bad for health primarily because they are high in omega-6 fatty acids, which can promote inflammation when consumed in excess. The "Hateful Eight" seed oils commonly advised to avoid include canola (from rapeseed), corn, cottonseed, grapeseed, soybean, sunflower, safflower, and rice bran oils

Why these seed oils are considered bad:

• High omega-6 content: These oils contain large amounts of linoleic acid, an omega-6 fatty acid that, in excess, may contribute to chronic inflammation linked to diseases such as heart disease, diabetes, obesity, and autoimmune disorders

• Processing and refining: Many seed oils undergo heavy chemical processing (including bleaching, deodorizing, and use of solvents like hexane), which strips nutrients and may introduce harmful compounds

• Oxidation and toxic byproducts: When these oils are heated repeatedly (common in frying and processed foods), they can oxidize and form toxic compounds that may harm health

• Association with processed foods: Seed oils are often found in ultra-processed foods high in sugar, salt, and unhealthy fats, which collectively increase health risks

Oils often recommended to avoid for better health:

• Canola oil
• Corn oil
• Cottonseed oil
• Grapeseed oil
• Soybean oil
• Sunflower oil
• Safflower oil
• Rice bran oil

Alternatives suggested:

• Saturated fats (such as coconut oil, palm oil)
• Extra virgin olive oil
• Avocado oil

These alternatives tend to be more stable when heated and have a healthier fatty acid profile

Contrasting views:

Some experts argue that seed oils are not inherently toxic and can provide heart-healthy fats if used properly, noting that the inflammation concerns are not conclusively supported by all research

. However, the general consensus is to limit intake of highly processed seed oils, especially in fried and processed foods. In summary, the seed oils most often considered bad for health are the highly processed ones rich in omega-6 fatty acids-specifically canola, corn, cottonseed, grapeseed, soybean, sunflower, safflower, and rice bran oils-due to their potential to promote inflammation and chronic disease when consumed excessively or repeatedly heated