Insoluble dietary fibres don't absorb water. It also includes hemicellulose and plant cellulose.
Insoluble dietary fibre doesn't dissolve in water. Whole wheat flour, nuts, beans, potatoes, green beans, and cauliflower are good sources.
Insoluble dietary fibre adds bulk and draws water to your stool thus, making it easier for stool to pass through the intestines.
Insoluble dietary fibre helps your body to process waste, improve bowel moments, and prevent and treat constipation.