[marze]

My brother has a friend who is the modern day equivalent. He travels North America by bike, eats pizza from cheap pizza restaurant dumpsters.

[nartho]

If he's eating from the dumpsters why not eat from the fancy restaurant's dumpster instead ?

[hyperbolablabla]

I can think of a few reasons. People tend to overorder pizza more than other stuff. Pizza is also more robust than other foods, so it survives being thrown away more than other things. It's also very satiating, comprising bread, dairy and meat.