Ingestion is the initial stage in the digestive process. It refers to the intake of food into the body, primarily through the mouth. This act, voluntary in nature, sets the stage for the subsequent steps in the digestive process.
During ingestion, the first stage of mechanical digestion also occurs. Teeth break down food into smaller pieces through a process known as mastication. Simultaneously, saliva moistens the food and begins the chemical breakdown of carbohydrates.