Comment by aziaziazi

Cellulose is one of the main constituant of plants and as a fiber, great for your gut:

> In human nutrition, cellulose is a non-digestible constituent of insoluble dietary fiber, acting as a hydrophilic bulking agent for feces and potentially aiding in defecation.

https://en.wikipedia.org/wiki/Cellulose

Workshop sawdust would be a bad idea though.