In American food, corn syrup is added to almost everything. This is done so that U.S. farmers can be subsidized for growing corn.
UK food doesn't have corn syrup, so it is sweetened in other ways, such as coating things with sugar. You probably notice the difference because it is a different type of sweetener. American food is so saturated with corn syrup that we don't even taste it anymore. As an example, I just randomly grabbed an (American) frozen dinner out of the freezer. Chicken chow mein. Yes, corn syrup is one of the ingredients.