Why do carnivores usually have simpler stomachs and shorter intestines than herbivores?

Carnivores in the order Carnivora typically possess simpler stomachs and shorter intestines because animal tissues are generally easier to digest than plant tissues.1

Unlike herbivores, which must consume plant matter containing cellulose—a material that higher animals cannot digest on their own—carnivores do not require complex, multichambered stomachs or specialized fermentation organs like the rumen or an enlarged cecum to break down their food. Consequently, the carnivore's digestive tract exhibits less compartmentalization and a decrease in the length and folding of the intestine, as they do not need the extensive surface area required by herbivores to extract nutrients from fibrous plant material.12