Why does drinking beer increase bowel movement?

This is from poopreport.com:

Beer is made from grain. Grain is a source of dietary fiber. The brewing process intensifies the potency of the fiber.

Beer is a source of soluble fiber which is derived from the cell walls of malted barley. A liter of beer contains an average of 20% of the recommended daily intake of fiber and some beers can provide up to 60%.

Beer = Fiber = Drop a Deuce ;)

Cheers.