Most trans fat is made through a chemical process that takes a liquid vegetable oil and adds hydrogen to it resulting in a "partially hydrogenated" oil. What does this look like? You know what solid shortening in a can looks like. You start with liquid oil, say soybean for example, add hydrogen and it becomes more solid at room temperature. This is an issue because trans fat can clog arteries, increase your lousy cholesterol also known as LDL and potentially cause heart disease. It lowers HDL (healthy) cholesterol and has no known health benefits.

Products with trans fat added have the words "partially hydrogenated" oil listed in the ingredients. Check out your labels. Do you see ZERO trans fat grams on the Nutrition Facts label but partially hydrogenated fat listed in the ingredients? This is because the label laws allow for a food to contain .5 grams of trans fat per serving and still call it zero. Typically this small amount is not an issue but it can become a problem if a cookie has .5 grams per serving and you eat 6 or 7. You have just consumed 3+ grams of trans fat. It's worth the time to read the labels.