A hamburger and fries are practically pre-chewed.  The bun is white flour blown full of air by the action of yeast and chemicals.  The hamburger is ground (“pre-chewed”) meat.  French fries are so processed that they are as soft as they can be without being liquid. 

It’s designed to be food that is not chewed more than two or three times.  It's also designed to be greasy so it will slide down your throat without much chewing.  If that's not enough, it's sold with giant sized drinks so you can wash down chunks of unchewed food that would be difficult to swallow otherwise. 

The faster you eat, the more you eat.  The more you eat, the more money the restaurant makes.