Weight Loss

This article is dedicated to weight loss as a manifestation of pathological conditions. Unintentional weight loss is a very serious symptom that should lead to medical examination and affected patient should be thoroughly investigated.


Clinically significant weight loss is considered as loss of at least 10% of person’s original weight in less than six months. For example, if someone weights 80 kilograms, an unintentional loss of 8 kilograms in few months should be considered as serious. The term “unintentional” is important as change in diet and physical exercise can cause a significant weight reduction that can be evaluated as positive (of course with the exception of anorexia nervosa).


Anorexia nervosa

Anorexia nervosa is a psychiatric disease related to weight loss, this time intentional. The disease occurs mainly in young girls and manifests as abnormally increased effort to lose weight by excessive exercise and deliberately reduced food intake.


Especially older people should be very aware of unintentional weight loss that must always be suspicious of malignant disease. Most unfortunately, weight loss belongs among symptoms of advanced metastatic tumor disease. Weight loss in cancer is usually caused by combination of more factors. Cancer tissue consumes nutrients and causes nutrient deficiency. The presence of cancer activates the immune system to overproduction of defensive substances including cytokines, interleukins and other pro-inflammatory molecules. These substances have an overall impact on psyche and metabolism. Breakdown of fat tissue is accelerated and loss of appetite occurs. Sudden rejection of meat is typical and relatively rapid weight loss is the result. In addition, tumors of the digestive tract can directly affect the process of digestion and food absorption.

Overactive thyroid gland

Increased production of thyroid hormones causes faster degradation of energy supplies. People begin to lose weight despite increased appetite.


Untreated diabetes manifests with weight loss, excessive thirst and frequent urination. The disease is widespread and can occur at virtually any age.

Addison's disease

This is a rare hormonal disorder that is caused by reduced production of hormone known as aldosterone that is produced by adrenal glands. It manifests by excessive thirst, weight loss, abdominal pain and vomiting. President Kennedy was one of the most known persons who suffered from this disease.

Vital organs deterioration

Heart, liver and chronic kidney failure lead to an overall deterioration of the patient that is followed, among others, by reduction of body weight. This is accentuated in alcoholics with liver cirrhosis and chronic liver failure who usually have insufficient nutrient intake.


Virtually all conditions leading to nutrient malabsorption consequently lead to weight loss. These are typically diseases of digestive tract, especially stomach, small intestine, gall bladder and pancreas.

Diagnostic approach

Medical history and physical examination should be targeted on individual problem, accompanying symptoms and current medication. Blood tests may show signs of inflammation (CRP, sedimentation rate), blood sugar level, thyroid gland hormones and fluctuations of major ions. Other examinations are targeted to exclude diseases of digestive tract such as stool examination, abdominal ultrasound, gastroscopy and colonoscopy. Psychiatric examination is appropriate in suspicion on anorexia nervosa.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources