Question

How does the presence of digestive enzymes affect an animal's diet?

Answer 1

Normal cell reactions such as digestion WITHOUT enzymes take a really REALLY long time. We would probably die without these helpful enzymes to speed up the rate at which food is broken down. Naturally, the types of enzymes the animal has will encourage the animal to consume the kinds of which contain those nutrients. For example, the human body cannot digest cellulose. This affects our diet because we will not go around consuming massive amounts of cellulose for the simple reason that we cannot gain anything from doing so.

This is also the reason for the gastric upsets that result from too much cellulose intake. Cows are able to digest it because they have bacteria in their gut which has the needed enzyme. The cow itself is still unable to make it, but this symbiotic relationship allows digestion to take place.