'Trans' fats are produced by the process of 'hydrogenation', whereby liquid vegetable oils (which contain natural polyunsaturated fats) are artificially hardened so that they can be used in many processed foods.
Trans fats are found in most margarines, commercially baked goods (such as cakes, biscuits, and pastries), fried foods (including crisps), and many sauces, salad dressings and ready meals.
Unfortunately, these fats have no known health benefits, and instead appear to have serious health risks. The safest level of trans fats in the diet would be zero.
These dangerous fats do not currently have to be listed by manufacturers on their food labels. However, whenever a food's ingredients include 'hydrogenated' or 'partially hydrogenated' fats or oils, trans fats will be present.
The US Food and Drugs Agency (FDA) has now insisted that from 2006, manufacturers must list trans fats among the ingredients on food labels.
Further information for consumers about trans fats is provided on their website via the link below.