What is trans fat and what foods in particular is it found in?

Baked goods. Meats have some transfats, but most are manmade. Transfats are made by hydrogenating oils, which turns them into solids (shortening). Transfats are used in processed foods b/c they last longer on shelf that way -- cookies/pie crusts/chips/popcorn/donuts/creamer/margarine. They raise LDL (bad) and lower HDL (good) cholesterol, which leads to heart disease. Saturated fats are just as bad!
Trans. Refers to the particular chemistry of the carbon chain that makes up the molecule. Cis is the form for the essential fatty acids that we require .Unfortunately trans fatty acids are in a great number of "man made" foods and proprietary foods state the concentration of them on the label.