Most of the people think that empty stomach creates the feeling of hunger but this is not true. Hunger has nothing to do with an empty stomach.
For example, a person who has fever may have an empty stomach, but he does not feel hungry. Similarly when a child is born, he does not feel hungry for several days.
When the blood gets depleted of nutritive materials, a message is sent to our brain by our body through nerves. The deficiency of nutritive materials is caused in the blood by the consumption of energy in the routine work.
A sick man remains in a state of rest and consumes small amounts of energy. He, therefore, does not feel hungry for several days.
Whenever there is a deficiency of nutritive food substances in the blood, a message goes to the ‘hunger centre’ of the brain. This centre acts like a brake on the activities of the stomach and intestines.
When the blood has sufficient nutritive substances, the hunger centre stops the activities of the stomach and intestines.
On the contrary when there is a lack of nutrition, the intestines and stomach become active. That is why you can hear your stomach rumbling when you are hungry.
The above information is reproduced from here.