Many edible vegetable and animal oils, and also fats, are used for various in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water. Oils are also used for flavoring and for modifying the texture of foods e.g. Stir Fry. Health advantages are claimed for a number of specific oils such as omega 3 oils (fish oil, flaxseed oil, etc), evening primrose oil and olive oil. Trans fats, often produced by hydrogenating vegetable oils, are known to be harmful to health.