Unintentional weight loss is a decrease in body weight that is not voluntary.

Weight loss will occur with decreased food intake, increased metabolism, or both. See also intentional weight loss.

There are many causes of unintentional weight loss including endocrine, gastrointestinal, neurological, psychiatric, and eating disorders (see anorexia nervosa), as well as nutritional deficiencies, infections, and tumors.

• Conditions that prevent food consumption such as painful mouth sores, newly applied orthodontic appliances, or loss of teeth
• Manipulative behavior (in children)
• Unrealistic expectations of caretakers (with children)
• Depression
• Malnutrition
• Loss of appetite
• Prescribed or over-the-counter drugs (including amphetamines, chemotherapeutic agents, laxative abuse, and thyroid medications)
• Drug abuse and smoking
• Unrecognized intentional weight loss
• Undiagnosed anorexia nervosa or bulimia
• AIDS
• Malignancy
• Acute infection
• Chronic infections such as tuberculosis
• Parasitic infections (particularly if you are from or have recently traveled to another country)
• Chronic diarrhea
• Hyperthyroidism

Practice moderation and maintain a balanced program in both diet and exercise. For weight loss caused by oral or dental problems, see the dentist. For weight loss caused by disease, follow prescribed therapy in treating the underlying cause.

• An adolescent daughter (or son) has an unrealistic self-image and seems to be dieting excessively.
• Weight loss is excessive (greater than 10% of normal body weight) and unexplained.
• Weight loss is accompanied by other unexplained symptoms.

The health care provider will obtain your medical history and will perform a physical examination.

Medical history questions documenting weight loss in detail may include the following:

• When did the weight loss begin?
• Has it been sudden or gradual?
• How much weight has been lost?
• Has appetite decreased?
• Has amount or kinds of food eaten changed?
• Has physical activity level increased?
• Has there been an illness?
• Have there been dental problems or mouth sores?
• Have stress or anxiety levels increased?
• Is there vomiting?
• Is there self-induced vomiting?
• Is there an apparent increased energy level?
• Has there been excessive physical exercise?
• Is there fainting?
• Is there occasional uncontrollable hunger with palpitations, tremor, and sweating?
• Has there been a change in vision?
• Is there increased sensitivity to cold or heat?
• Is there constipation or diarrhea?
• Is there increased thirst or drinking?
• Is there increased urinary output?
• Has there been any hair loss?
• What medications/drugs are being taken?
  • Diuretics?
  • Laxatives?
  • Alcohol?
  • Street drugs?
  • Has there been severe depression?
  • How is the body image -- are you aware of the weight loss? Are you pleased or concerned?

The physical examination may include a general physical examination and a measurement of the body weight.

Diagnostic tests that may be performed include the following:

• Nutritional assessment
• Blood tests including a chemistry profile

Psychological counseling may be recommended in cases where anorexia nervosa or depression are the cause of the weight loss. In the early stages, anorexia nervosa may be best treated in a hospital with close supervision. Even after anorexia nervosa has apparently been cured, the individual should visit the doctor periodically. Relapse is not uncommon.

For weight loss caused by a chronic illness, tube feeding may be administered in order to maintain nutrition and to prevent edema, poor healing, and muscle wasting.

The patient may be referred to a dietitian for nutritional counseling.