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Approach to the patient with unintentional weight loss

Arthur T Evans, MD, MPH
Renuka Gupta, MD, FHM, FACP
Section Editor
Joann G Elmore, MD, MPH
Deputy Editor
Howard Libman, MD, FACP


Weight loss is a common problem seen by generalists. Patients who are overweight or obese may intentionally lose weight to improve their health. However, progressive unintentional (involuntary) weight loss often indicates a serious medical or psychiatric illness.

This topic will discuss the approach to unintentional weight loss in the adult patient. Weight loss and nutritional issues in older adults and weight loss or inadequate weight gain in children and adolescents is discussed separately. (See "Geriatric nutrition: Nutritional issues in older adults" and "Failure to thrive (undernutrition) in children younger than two years: Etiology and evaluation" and "Poor weight gain in children older than two years of age".)

Weight loss in the management of obesity is also discussed separately. (See "Obesity in adults: Overview of management" and "Obesity in adults: Dietary therapy".)


Unintentional weight loss – Unintentional weight loss is also referred to as involuntary or unintended weight loss [1]. This term excludes weight loss as an expected consequence of treatment (eg, weight loss from diuretic therapy in patients with heart failure) or as a result of a known illness. Clinically important weight loss is generally defined as loss of more than 5 percent of usual body weight over 6 to 12 months [1,2].

Clinically significant weight loss and nutritional issues in older adult patients is discussed elsewhere. (See "Geriatric nutrition: Nutritional issues in older adults", section on 'Weight loss'.)

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Literature review current through: Nov 2017. | This topic last updated: Sep 07, 2017.
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