A Fast Club member mentioned to me two weeks ago how much fasting has changed her digestive process. She commented on how she had more frequent and "stronger" bathroom runs following her fast days (doing 36Power Fasts). She asked me if that was strange or normal.
I told her that I've experienced the exact same pattern. The day after a fast I feel like my body purges much more than other days.
This article mentions how many people have output that is "black like tar" after fasting. This makes a lot of sense. Our bodies have 30 feet of intestines (25 in the small intestine and 5 feet in the large). When we fast it allows our body to remove impacted fecal matter from the walls of our intestines and expunge it. The longer the fast, the greater our intestines ability to cleanse and repair itself. When these passage ways open up we can digest our food easier and provides other health benefits like better skin complexion and tone.
One of the things I value the most about fasting is that it makes us stronger (and fresh) from the inside out.