At that time, you feel "I'm hungry! This is felt not by the stomach, but by the brain. This mechanism is a little complicated.
The brain, not the stomach, is responsible for the feeling of hunger. is felt by the "hunger center" in the brain. The hunger center is responsible for informing the body that it is hungry. For example, when the stomach is empty and the hunger center gives the order, the mouth begins to spit and the stomach and intestines begin to make a preparatory movement called a "good movement. Then, we can clearly tell that we are hungry.
By the way, in addition to the hunger center, there is another center in the brain called the "satiety center. This center literally tells us that our stomach is full. When food enters the stomach, the stomach swells with food and tells the hunger center that there is enough to eat, thereby suppressing appetite.
In this way, when we stop spitting or slow down the speed at which the stomach and intestines move, we know that our stomach is full. When we say that we are hungry, we are not talking only about our stomachs; we are also using our brains.