In order to establish whether someone has bulimia nervosa, a mental health professional needs to investigate whether the following criteria are present:

• Recurrent episodes of binge eating. An episode of binge eating is characterised by both of the following:
  • eating, in a discrete period of time (e.g. within any 2-hour period), an amount of food that is definitely larger than most people would eat during a similar period of time and under similar circumstances
  • a sense of lack of control over eating during the episode (e.g. a feeling that one cannot stop eating or control what or how much one is eating)