The following is considered the "text book" definition of Bulimia Nervosa to assist doctors in making a clinical diagnosis... it is in no way representative of what a sufferer feels or experiences in living with the illness. It is important to note that you can still suffer from Bulimia even if one of the below signs is not present (also see the Signs and Symptoms section). In other words, if you think you have Bulimia, it's dangerous to read the diagnostic criteria and think "I don't have one of the symptoms, so I must not be Bulimic".

Recurrent episodes of binge eating. An episode of binge eating is characterized 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)
Recurrent inappropriate compensatory behavior in order to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise.
The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice a week for 3 months.
Self-evaluation is unduly influenced by body shape and weight.
The disturbance does not occur exclusively during episodes of Anorexia Nervosa.
Purging Type: during the current episode of Bulimia Nervosa, the person has regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas
Nonpurging Type: during the current episode of Bulimia Nervosa, the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas