Weight loss

"The loss of 5% of body weight in a period of 6 to 12 months requires the immediate execution of additional studies".


When a patient comes in for a weight loss consultation, before undertaking an extensive search it is important to verify that weight loss actually occurs and measure the time frame in which it occurred.

Almost 50% of the patients who claim to have experienced significant weight loss do not actually present any objectively measurable change in their body weight.

It is not uncommon to see patients who have not noticed that they have actually lost weight to a relevant degree.

Any significant weight loss that a previously healthy person has not deliberately sought out usually indicates the existence of a systemic disease.

That is why it is important to systematically quantify the body weight of each patient in the consultation.

What are the symptoms of weight loss?

Patients suffering from pathological conditions that justify weight loss usually have signs and symptoms that allow suspecting the condition of a certain organ, apparatus or body system.

Tumors of the digestive system, including those of the pancreas and liver, can early impair food intake and cause weight loss before other symptoms appear.

Lung cancer can manifest itself in the form of post-obstructive pneumonia with dyspnea, or cough and hemoptysis, but it also usually occurs without symptoms and should be suspected even in non-smokers.

Depression and isolation can lead to significant weight loss, particularly in the elderly. In chronic obstructive pulmonary disease and congestive heart failure, anorexia and increased energy expenditure at rest may occur.

Weight loss can be the first manifestation of some infectious diseases, such as HIV infection, tuberculosis, endocarditis, and fungal and parasitic infections.

Hyperthyroidism or pheochromocytoma increases basal metabolism; elderly people with apathetic hyperthyroidism may experience weight loss and weakness, with few other manifestations of thyrotoxicosis.

New-onset diabetes mellitus is often accompanied by weight loss from glycosuria and loss of the anabolic effects of insulin.

Adrenal insufficiency can be suspected by hyperpigmentation, hyponatremia and hyperkalemia. 

Most common symptoms:

  • Weight loss.
  • Fatigue.
  • General malaise.

Have you lost weight unjustifiably?

A study of your weight loss may be necessary

How is weight loss diagnosed?

Look for signs or symptoms that are linked to conditions that commonly cause weight loss, such as fever, aches, dyspnea or cough, palpitations, changes in urination, and signs of neurological disease.

Also look for gastrointestinal disorders, such as difficulty eating, dysphagia, anorexia, nausea and changes in bowel habits.

Travel and consumption of cigarettes, alcohol and all kinds of medications should be asked about, as well as a history of other diseases or surgical operations, and the diseases of family members.

Risk factors for HIV infection should be assessed, and signs of depression or dementia should be looked for.

The physical examination is complete and is assessed device by device to see if there are any alterations. In men, a rectal examination should be performed to feel the prostate and a fecal occult blood test should be performed; and all women should undergo a gynecological examination, even if the womb has been removed.

Laboratory tests should consist of a blood count with glucose, electrolytes, liver and kidney function tests, calcemia and TSH, urinalysis, and a chest x-ray.

In all cases, the recommended selective detection tests (screening) for some cancers should be updated/repeated according to gender and age group, such as mammography and Pap smears.

If there are gastrointestinal signs or symptoms, the high or low endoscopy (or both) and the abdominal study by CT scan or MRI, have a relatively high rate of diagnostic confirmation.

If no cause is detected to explain the weight loss, it is advisable to schedule careful clinical monitoring of the patient, rather than insisting on other tests without any clinical orientation.

Where do we treat it?


The Department of Internal Medicine
of the Clínica Universidad de Navarra

Its integrative vision and polyvalence allow us to provide the best medical assistance to multipathological and multisymptomatic patients, who present a difficult diagnosis or who suffer from prevalent diseases of a hospital nature.

Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clínica?

  • State-of-the-art diagnostic technology.
  • Quick diagnosis to start the most appropriate treatment early.
  • Teamwork with the rest of the professionals in the Clinic.

Our team of professionals