>>12307817Fiber keeps your digestive system healthy. Much of it acts like a broom, sweeping waste products out of your digestive tract, giving peristalsis something to push against.
It's also usually 'prebiotic', meaning it contains things your body can't use, but your intestinal flora *can* use, and as you well know they exist in a symbiotic relationship with your digestive system, getting the nutrients they need, and excreting substances that are beneficial to *you*, like vitamin B12, for instance.
