Why do we eat plants if we can’t digest cellulose, ie, plant cell wall?

Question

Title says all. Plant cells are covered by cell wall made of cellulose. The human body doesn’t have the enzyme cellulase to digest it, so why do we eat them? Do they just pass through us? If so, why are they ‘healthy’?

In: 55

Answer 1

It helps scrub out large intestines so sticy stuff doesn’t build up. Our grandmas called it “roughage.”