Actually, breathing is the body’s top priority. Without oxygen, even for a few minutes, the body shuts down. In fact, breathing makes eating more complicated. We shut off our airway briefly with every swallow. However, if breathing is challenging for the body, sometimes, we sacrifice our skills for safely chewing food and incorporate breathing through the mouth at the same time. This can put one at risk for inhaling food while trying to coordinate chewing and breathing.
We should see people chewing with their mouths closed, not only to avoid bugging their meal partners, but more importantly so that they maintain nasal breathing while chewing. Next time you see somebody chewing with their mouth open, try and cue them “breath through your nose while you chew” rather than “chew with your mouth closed”.