Trans-fat containing margarine used in cakes can be substituted by olive oil without affecting textural properties and flavour, a Greek study has found. Researchers from the University of Thessaloniki found that despite the characteristic flavour of olive oil, a panel of tasters discerned no difference. Fats from vegetable oils may have undergone hydrogenation processes, which can lead to the production of trans- fats. These fats have been shown to have detrimental health effects such as reduced levels of HDL-cholesterol and increased levels of LDL cholesterol.