Polyphagia or hyperphagia is excessive hunger or increased appetite.
It is a medical sign meaning excessive hunger and abnormally large intake of solids by mouth. It can be caused by disorders such as diabetes, Kleine–Levin syndrome (a malfunction in the hypothalamus), and the genetic disorders Prader–Willi syndrome and Bardet–Biedl syndrome. Knocking out vagal nerve receptors has been shown to cause hyperphagia.
Causes of increased appetite include:
Polyphagia usually occurs early in the course of diabetic ketoacidosis. However, once insulin deficiency becomes more severe and ketoacidosis develops, appetite is suppressed.