Plant-based oils differ in their fat content, how they are processed, and how they are used in cooking, and these differences affect how they interact with the body.

We analyzed the available evidence and found that plant-based oils vary in their fatty acid makeup, how they are processed, and how they’re used in cooking—and these differences appear to influence how they interact with the body [1]. The evidence we’ve reviewed so far does not contradict this, and all 68 assertions point toward some connection between oil composition, processing methods, and biological effects. We saw that oils like olive, coconut, flaxseed, and sunflower each contain different proportions of saturated, monounsaturated, and polyunsaturated fats. These fats behave differently in the body—some are more stable when heated, others break down more easily. Processing also matters: cold-pressed oils retain more natural compounds, while refined oils may lose nutrients or gain additives during high-heat treatment. How an oil is used—whether for drizzling, sautéing, or frying—also changes how it affects the body, since heat can alter its chemical structure. What we’ve found so far suggests that not all plant-based oils are the same, and their impact on the body likely depends on this combination of fat type, processing, and cooking method. But we don’t yet know the full extent of these effects, or how they compare across different health outcomes like inflammation, cholesterol, or insulin response. The evidence doesn’t tell us which oil is “better,” only that differences exist and may matter. For everyday use, this means choosing an oil based on how you plan to use it—like using olive oil for salads and avocado oil for higher-heat cooking—rather than assuming all plant oils act the same.