Trans fatty acids, also known as trans fat, is an artery-clogging fat that is formed when vegetable oils are hardened into margarine or shortening. It is found in many other foods besides margarine and shortening, however, including fried foods like french fries and fried chicken, doughnuts, cookies, pastries and crackers. In the United States, typical french fries have about 40 percent trans fatty acids and many popular cookies and crackers range from 30 percent to 50 percent trans fatty acids. Doughnuts have about 35 percent to 40 percent trans fatty acids. Trans fat is known to increase blood levels of low density lipoprotein (LDL), or "bad" cholesterol, while lowering levels of high density lipoprotein (HDL), known as "good" cholesterol. It can also cause major clogging of arteries, type 2 diabetes and other serious health problems, and was found to increase the risk of heart disease. Many food companies use trans fat instead of oil because it reduces cost, extends storage life of products and can improve flavor and texture.