Photo of that fat man that Casey posted. That guy has "Subway - eat fresh" tattooed in between Burger King and KFC. I wouldn't expect a guy that looks that fat to eat something as sophisticated as Subway sandwiches. lol
There's nothing sophisticated about it, their bread is frozen for literally months before they cook it, and most of their fillings are incredibly bad for you (steak and cheese, meatballs, all the meats). The cheese is basically plastic, the sauces are watered down.
I occasionally get myself a salad sub, heavy on the jalapenos, but everything else they serve is either incredibly bad for you or of minimal nutritional value.
They really aren't THAT much better than the likes of Burger King and McDonalds. But that small amount that they are better, is what they've played upon in order to get that position as the largest chain.