How does the human body prevent an internal energy levels from becoming too low

The nervous system transmits feeling of of fullness to the digestive system which signals metabolism to stop
The digestive system transmits feelings of hunger to the brain which innate eating
The digestive system transmits fillings of fullness to the nervous system which signals metabolism to stop
The brain treatments feelings of hunger so digestive system which initiates eating

The correct answer is: The brain processes feelings of hunger and sends signals to the digestive system to initiate eating.