Well, you don't want to choke, do you? If we swallowed food whole, like many animals do, puts us at risk of trapping a large chunk of food in our throats which we can't dislodge without another's help. A horrible experience! Even a small chunk of something hard such as raw carrot, can result in this.
So we chew. In this way, we break down the food's fibers until they are soft enough to slide down our delicate throats without harm. We also aid digestion by doing this. You know how wretched you feel when you have painful gripes in your stomach? This is often your gut trying to deal with digestion, working on food fibers that have not been sufficiently broken down.
