Insight into illness is an important topic in the treatment of eating disorders. In particular, patients with anorexia nervosa do not recognize the seriousness of malnutrition nor sense that they are unwell. These phenomena make the treatment extremely difficult. In some anorexic patients, it is known that their beliefs about their own body are not correctable and are delusional in nature.
 Some reports have pointed out that in terms of preoccupation and distress caused by the pathological beliefs, anorexic patients score worse than other psychiatric patients such as schizophrenics. Problematic behavior such as manipulation of weight before weighing is often observed on a ward treating anorexic patients. However, pointing out the badness of behavior only pushes patients to leave the treatment early. Confrontation is necessary but the psychological aspects behind the behavior must be discussed with the patients. With discussion on why the patient had to behave that way, patients themselves start to recognize that part of their behavior is indeed controlled by anorexia nervosa.
 Motivation for treatment has also been the interest of researchers in the field of eating disorders. Motivational interviewing (Miller and Rollnick) is a recommended treatment method and is best applied for relatively chronic patients in whom anorexia has become a life style. Early cases often see their weight loss as a success and it is difficult for them to consider the negative side of it. However, it is possible to encourage them to reflect on the various changes in them that have occurred since they lost weight. For example, the use of a pie chart that encourages the patient to draw how much their weight concern occupies their mind. Many patients admit that they are aware of these changes and that they are distressed with the preoccupation. They are often aware of the point at when they started to notice the change in their mind. Many are even aware at which weight this started to occur. This weight can be used as a treatment target at the first stage of treatment. Very few patients at the early stage of treatment have insight into why they should reach a standard weight. Going back to the weight at which the preoccupation started can be a manageable initial target.
 With bulimia nervosa, patients can hide their symptoms for a long time and the percentage of patients who seek help is smaller than that of anorexics. However, the patients who come for treatment do so of their own will and they have a strong sense that they have symptoms of eating disorders. They have a full insight into illness in that sense but their image of treatment can be quite unrealistic. Some want zero symptoms immediately, after years of binging and purging;others think talking their stress off, in one long session, should normalize the situation.
 Insight into illness is not simply the recognition of the existence of psychiatric symptoms. Treatment is stabilized when the image of the course of treatment and the hypotheses on the possible causes and exacerbating factors in the future are shared between the patient and the professional. Labeling certain behavior as pathological and abnormal does not help patients gain insight. Encouraging patients to observe the change and cultivate their interest in the change help them acquire the appropriate insight into illness.
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