I am a 6th grade teacher and the students are currently learning about the digestion process from chewing to elimination. One of the students asked, "Why is our poop always brown?" I thought this was a good question because, as they pointed out, our food is all kinds of colours.
Thanks for answering...

Facing the FAQs: Why Is Poop Brown? (http://www2.oprah.com/health/yourbody/slide/slide_yourbody_embarrassing_103.jhtml) Hope this helps.