Extra virgin olive oil consists mainly of fats, but it also contains much smaller amounts of phenolic and aromatic compounds. Their profile can change during cooking: temperature and duration matter, as do water and the foods in the recipe.
A 2015 study of potato, pumpkin, tomato and aubergine prepared with EVOO compared frying, sautéing and boiling. The researchers observed transfers of phenolic compounds between oil, vegetables and cooking liquid, with results varying by technique and food. This is food chemistry, not proof that one method prevents disease. [Ramírez-Anaya et al. — Phenols and the antioxidant capacity of Mediterranean vegetables prepared with extra virgin olive oil using different domestic cooking techniques, Food Chemistry, 2015]
In a later study of the same kinds of preparation, total phenolic content and antioxidant capacity measured in the oil decreased after cooking; during boiling, some compounds moved into the water. The result shows why the oil left in the pan alone cannot describe the whole dish. [Ramírez-Anaya et al. — Changes in the Antioxidant Properties of Extra Virgin Olive Oil after Cooking Typical Mediterranean Vegetables, Antioxidants, 2019]
A domestic sautéing model published in 2020 found that temperature reduced the oil’s polyphenols, while duration affected some individual compounds but not total phenolic content in the same way. More or less of one marker does not automatically make a dish “healthier”. [Lozano-Castellón et al. — Domestic Sautéing with EVOO: Change in the Phenolic Profile, Antioxidants, 2020]
In practice, EVOO can be used raw when aroma and sensory character are the priority, or in cooking when the recipe calls for it. Choose time and temperature for the dish rather than turning these studies into a therapeutic dose. The cited research did not test Cook with Olive Oil or clinical outcomes. Sources checked on 13 September 2026.