Hydrogenation is a process that adds hydrogen to liquid unsaturated fats. The process makes the fats more saturated and solid. Hydrogenation improves shelf life, cooking properties, and flavor. However, hydrogenation does have drawbacks. Hydrogenation makes an unsaturated fat saturated and creates trans-fatty acids. Both saturated fats and trans-fatty acids increase the risk for high blood cholesterol and heart disease. People should limit their intake of products with the words hydrogenated fat, hydrogenated oil, or partially hydrogenated oils.