Better Medicine states that hunger is the result of a complicated group of interactions controlled by the body's endocrine, digestive and neurological systems. These systems send chemicals to the brain to indicate both hunger and fullness. When a person consistently experiences excessive hunger, it can be a sign of illness.
Some of the diseases that can cause severe hunger pains include Graves' disease, hyperthyroidism and hypoglycemia, a condition that can progress to insulin shock and requires immediate medical attention. Better Medicine also states that excessive hunger sometimes has an emotional basis. Other causes include pregnancy and a reaction to certain prescription medications.