Here are some scans from a book I bought in Japan in the past. It's called 'Uncocoro for Natural Unco Life' by Bunpei Yorifuji and Koichiro Fujita. Its subject is intestinal health and focuses on giving the reader techniques and advice to help achieve healthy and regular poo. It's in Japanese with very clear illustrations presented beautifully using mostly brown and yellow spot-colours. Appropriate.
It seems that the term 'Unco' covers human and animal waste.
As well as general waste.
Your body and it's functions are part of a larger system.
Your diet and it's influence on your internal bacterium and flora.
When I was a kid, I had a picture book called 'How Your Body Works'. It used factories or castles under siege as analogies for bodily functions and helped me understand the mechanical nature of our bodies. I was obsessed with that book. 'Uncocoro for Natural Unco Life' has a similar approach, but is a bit more... specific.