What are trans fats? Trans fats are a man-made saturated fat. They are made by taking hydrogen gas and forcing it into oil, so now the essential fatty acids, (or "healthy fat") is converted to a different form chemically, a new type of fatty acid, called a trans fat. Trans fats are found in crisco, margarine and many packaged and snack foods. The hydrogenated oil found in trans fats are more stable, prolonging shelf life of most packaged foods. Hydrogenated oil will not go rancid as quickly as untreated oil and it has a higher melting point, often used in frying and pastries.
Trans fatty acids work to increase LDL, or "bad" cholesterol, and they also decrease HDL cholesterol, which is "good" cholesterol. This means that the fats in hydrogenated oil are far more damaging than even saturated fats, which have already determined to be harmful. There is also evidence to suggest that trans fatty acids may bioaccumulate in the body, because the digestive system has difficulty figuring out what to do with them. As a result, a diet high in trans fats will result in weight gain. Studies have shown that consumption of hydrogenated oil has been linked with diabetes, coronary disease, and obesity.
You should limit the amount of natural saturated fats you eat, but completely avoid trans fats. Read the ingredients on food labels. If you see “partially hydrogenated” or “hydrogenated” oils, that means it has trans fats....so stay away! (American Academy of Family Physicians).