We're wired to respond that way.
Some people feel nauseous, vomit or have diarrhea.
Essentially the stomach is a muscular sack for the storage and release of food into the small intestine. By nature, it's an agitator whose churning, messy activity allows us to digest food and stay alive. When we're hungry, it reacts automatically with hunger pangs, or growling, so we're motivated to eat. When we're sated, we stop. When we have to have a bowel movement, we just do.