What keeps food moving in only one direction through the digestive system?

Food moves in one direction through the digestive system primarily due to coordinated muscle contractions known as peristalsis. These rhythmic contractions occur in the smooth muscles lining the digestive tract, pushing food forward from the esophagus to the stomach and through the intestines. Additionally, one-way valves, or sphincters, at various junctions prevent backflow, ensuring that the food continues its journey in a linear path.