The food industry has a significant number of people employed whose whole job is to make you think foods are healthier than they are and get you to eat more of them. I mean it's not by accident that almost every food in the supermarket ended up with some health claims on the box (my favorite examples of this are, like, "natural" eggs and "gluten-free" meats).

That's assuming you're buying your own food; if you're eating in a restaurant or something you don't even really know what you are consuming.