That Partially Hydrogenated Oil is a food manufacturers way of making unsaturated fat a solid form, similar to butter. This is an inexpensive way for manufacturers to extend shelf life and add flavor to the food. The problem is that these oils, when hydrogenated, turn into a dangerous trans fat. It increases cholesterol levels and your body has a hard time digesting it.
Here is another good reason to always check your nutrition fact labels. If you see Hydrogenated oils on the ingredient list of the nutrition fact label, I recommend just putting it back!