What is worse trans fat or saturated fat?

In order to make a trans fat, an unsaturated fat must be heated to high temperatures, which greatly increases the rate of oxidation. The amount of oxidated fats in the diet is one of the chief factors in the development of atheromas in arteries. So while when eating unsaturated fats you will generally be consuming some oxidized fatty acids, when you eat trans fats you will be consuming a substantially larger quantity.