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

Because they don’t run. Easier to supplement with digestible fibers than have to hunt enough for a pure carnivore diet. Omnivores such as humans tend to have evolutionary advantages because of this.

Answer 2

To raise the hopes of vegans just before we shatter them by ordering a steak with our salad.

Answer 3

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