Trans fats are artificially made by hydrogenating liquid vegetable oils, giving them a longer shelf life and a more solid consistency. Hydrogenation involves adding hydrogen atoms to the carbon atoms in the oil, which in turn creates a more saturated fat. The process of hydrogenation also creates trans fats, which are believed to be the most unhealthy type of fat. Trans fats can increase the risk of coronary heart disease, stroke, and Type 2 diabetes. The FDA has recommended that trans fats be limited as much as possible in foods.