Loud banging after flush

We've been getting a loud pipe banging noise after flushing the toilet, in fact you can even feel the vibration in the floors. Kind of scary. But get this - it only happens when flushing poop. And only to that one toilet it seems. Flushing just liquid waste or toilet paper doesn't seem to cause any noise. Is this a problem? How might I go about fixing it? More fiber in diet? :eek: