Chewing
The first mechanical and enzymatic stage of digestion, which conditions the rest of the digestive process and helps regulate food intake.
Chewing is the first stage of digestion, and it works in two ways. Mechanically, it breaks food into pieces and increases the surface accessible to enzymes. Chemically, it mixes food with saliva, whose amylase begins breaking down starch in the mouth.
It also triggers the cephalic phase of digestion: taste and smell signals prepare the stomach and pancreas to receive the meal by starting their secretions. Food swallowed without being chewed arrives in a digestive tract that has not prepared itself.
Its role in fullness is the most underestimated. Hormonal fullness signals take fifteen to twenty minutes to reach the brain: eating fast means finishing your plate before the message arrives. Studies comparing eating speed and amounts consumed regularly show a significant difference, with identical composition.
This also sheds light on the difference between a whole food and its processed version: an apple requires chewing work that apple purée or juice removes, even though the sugar content is comparable. This is one of the reasons why foods that need to be chewed are more filling.