Trans fats are unsaturated fatty acids that are used commercially in foods. They are made from regular cooking oils, such as soy oil, but they have been chemically changed to be more shelf-stable, and be able to withstand high cooking temperatures, such as those used in deep-frying. This change in chemical structure also has resulted in trans fats having negative health effects. Trans fats have been shown to lower high-density lipoprotein (HDL) cholesterol, aka "good" cholesterol, and raise low-density lipoprotein (LDL) cholesterol, aka "bad" cholesterol. As a result, they can raise a person´s risk for heart disease.