Weight loss can be intentional, such as from dieting and exercise, or unintentional and be a manifestation of illness. Weight loss can result from a decrease in body fluid, muscle mass, or fat. A decrease in body fluid can come from medications, fluid loss, lack of fluid intake, or illnesses such as diabetes. A decrease in body fat can be intentionally caused by exercise and dieting, such as for overweight or obesity. Weight loss is normal after pregnancy. Other causes of weight loss include, but are not limited to, cancer, viral infection (such as CMV or HIV), gastroenteritis, parasite infection, depression, bowel diseases, and overactive thyroid (hyperthyroidism).
The loss of weight and lack of nutrition associated with a chronic illness is referred to as cachexia. Unexplained, unintentional weight loss is often a result of illness and should be evaluated by a health care professional.
REFERENCE:
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
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Causes of Weight Loss
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Addison's Disease
Addison disease is a hormonal (endocrine) disorder involving destruction of the adrenal glands (small glands adjacent to the...
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Alcoholism
Alcoholism is a disease that includes alcohol craving and continued drinking despite repeated alcohol-related problems, such as...
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Amebiasis (Entamoeba histolytica Infection)
Amebiasis is an infection caused by an amoeba. Signs and symptoms include bloody stools, abdominal pain, weight loss, fever, and...
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Amyloidosis
Amyloidosis is a group of diseases resulting from abnormal deposition of certain proteins (amyloids) in various bodily areas. The...
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Anorexia
Anorexia is an eating disorder characterized by markedly reduced appetite or total aversion to food. Anorexia is a serious...
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Arthritis
Arthritis is inflammation of one or more joints. When joints are inflamed they can develop stiffness, warmth, swelling, redness...
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Balamuthia
Balamuthia mandrillarisis is an ameba that lives in dust and soil. Signs and symptoms of Balamuthia include fever, nausea and...
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Bile Duct Cancer (Cholangiocarcinoma)
Bile duct cancer (cholangiocarcinoma) is a rare type of cancer that arises from cells that line the drainage system from the...
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Bone Cancer
Bone cancer is a rare type of cancer that occurs in cells that make up the bones. Primary bone cancer that arises in bone cells...
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Brucellosis
The bacteria Brucella causes brucellosis, an infectious zoonotic disease in humans. Symptoms and signs include fatigue, fever,...
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Bulimia
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Burkitt Lymphoma
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Cancer
Cancer is a disease caused by an abnormal growth of cells, also called malignancy. It is a group of 100 different diseases, and...
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Cancer Risk Factors
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Colon Cancer
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Connective Tissue Disease
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COPD (Chronic Obstructive Pulmonary Disease) Symptoms, Causes, Stages, Life Expectancy
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Crohn's Disease vs. Ulcerative Colitis (UC)
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Cryptosporidiosis
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Cyclospora Infection (Cyclosporiasis)
Cyclospora cayetanensis is a parasite that causes infection when humans ingest food contaminated with feces from an infected...
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Dehydration
Dehydration is the excessive loss of body water. There are a number of causes of dehydration including heat exposure, prolonged...
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Dementia
Dementia is defined as a significant loss of intellectual abilities such as memory capacity, severe enough to interfere with...
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Depression
Depression is an illness that involves the body, mood, and thoughts and affects the way a person eats and sleeps, the way one...
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Diabetes (Type 1 and Type 2)
Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are...
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Diabetes Insipidus
Diabetes insipidus is a condition in which the patient has frequent urination. Symptoms of diabetes insipidus include irritable,...
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Esophageal Cancer
Esophageal cancer is a disease in which malignant cells form in the esophagus. Risk factors of cancer of the esophagus include...
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Fitness
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Gastroesophageal Junction Adenocarcinoma
Gastroesophageal junction adenocarcinoma is cancer that forms in the area where the esophagus joins the stomach. Having GERD and...
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Giant Cell Arteritis (GCA or Temporal Arteritis)
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Graft Versus Host Disease (GVHD)
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Graves' Disease (Symptoms, Causes, Diet, Treatment Options)
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Hodgkin's Disease
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Human Immunodeficiency Virus (HIV)
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Hyperthyroidism (Symptoms, Causes, Treatment Medication, Diet)
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Irritable Bowel Syndrome (IBS)
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Kidney Cancer
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Leishmaniasis
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Leukemia
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Lung Cancer
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Mantle Cell Lymphoma (MCL)
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Marburg Virus Disease
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Multiple Myeloma
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Non-Hodgkin's Lymphoma
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Obesity
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Pancreatic Cancer
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Pancreatic Neuroendocrine Tumors (Islet Cell Tumors)
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Parkinson's Disease
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Polymyalgia Rheumatica
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Relapsing Polychondritis
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Sarcoidosis
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Teen Depression
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Thymoma
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Type 2 Diabetes
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Other Causes of Weight Loss
- Bowel Obstruction
- Dental Problems
- Infections (Parasites)
- Malabsorption
- Medications (Both Prescription and Nonprescription)
Examples of Medications for Weight Loss
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