Trans fat is the common name for a type of unsaturated fat with trans- isomer fatty acid(s). Trans fats may be monounsaturated or polyunsaturated.Most trans fats consumed today are industrially created by partially hydrogenating plant oils — a process developed in the early 1900s and first commercialized as Crisco in 1911. The goal of partial hydrogenation is to add hydrogen atoms to unsaturated fats, making them more saturated. These more saturated fats have a higher melting point, which makes them attractive for baking and extends their shelf-life. Another particular class of trans fats, vaccenic acid, occurs naturally in trace amounts in meat and dairy products from ruminants.Unlike other dietary fats, trans fats are neither required nor beneficial for health and, in fact, the consumption of trans fats increases one's risk of coronary heart disease by raising levels of "bad" LDL cholesterol and lowering levels of "good" HDL cholesterol. Health authorities worldwide recommend that consumption of trans fat be reduced to trace amounts. Trans fats from partially hydrogenated oils are generally considered to be more of a health risk than naturally occurring oils.Chemically, trans fats are made of the same building blocks as non-trans fats, but have a different arrangement. In trans fatty acid molecules, the hydrogen atoms bonded to pair(s) of doubly bonded carbon atoms (characteristic of all unsaturated fats) are in the trans rather than the cis arrangement. This results in a straight, rather than kinked, shape for the carbon chain, more like the straight chain of a fully saturated fat.