About 0.5 - 1.0 % of late adolescent or adult women meet criteria for the diagnosis of Anorexia Nervosa while approximately 1.0 - 2.0 % of late adolescent and adult women meet criteria for the diagnosis of Bulimia Nervosa.

When looking at the symptoms more generally (and not looking at satisfying a full diagnosis), about 10% or more of late adolescent and adult women report symptoms of eating disorders, which are also concerns for physical and emotional health. In addition, the vast majority of American women are dissatisfied with their appearance and/or body. Some will develop full-blown eating disorders, some will experience symptoms but will not meet diagnostic criteria, and others may not experience difficulties. Although treatment could be helpful at any point in time, it is important not to wait until one has a full blown eating disorder; early treatment may prevent the manifestation of a more serious disorder.

Obesity is not a psychiatric illness. Rather, it is included in the International Classification of Diseases as a general medical condition. This is because obesity has not been consistently associated with any psychological syndrome. Nevertheless, many patients who are obese experience mental disorders alongside including depression, anxiety, binge eating, pain, and other diseases and disorders.

Obesity is measured by body mass index or BMI (calculated as weight in kilograms divided by height in meters squared).

Obesity is a complex interaction of genetics and environmental causes. Depending on level of BMI, treatment entails diet, physical activity, behavior modification, medication, or bariatric surgery.