Overview, Causes, & Risk Factors
Weight loss occurs when a person burns more calories, or energy, than he or she takes in. It may be deliberate or unintentional.
What is going on in the body?
A loss of weight is due to one of three factors:
fewer calories are consumed
more calories or energy are burned off during activity
a person's basic metabolism at rest speeds up
Weight loss may or may not be intended. Unplanned weight loss is often a sign of serious illness.
What are the causes and risks of the condition?
Some of the causes of weight loss are as follows:
cancer, including colon cancer, lung cancer, cancer of the pancreas, or leukemia
conditions that affect the ability of the intestines to absorb food and other nutrients
diabetes, a condition that results in high blood glucose levels
digestive diseases, such as inflammatory bowel disease or peptic ulcers
hormone imbalances, such as an increased thyroid hormone level known as hyperthyroidism
increased level of physical activity, due to exercise or manual labor
infections, such as HIV or tuberculosis
intake of fewer calories
medicine or drugs, such as amphetamines, ephedrine, cocaine, heroin, or alcohol
psychiatric conditions, such as depression, anorexia, or schizophrenia
severe kidney, liver, or heart disease
Other causes of weight loss are also possible. Sometimes a cause cannot be found.
Symptoms & Signs
What are the signs and symptoms of the condition?
Those who lose weight through physical activity and eating a proper diet have little to worry about. If anything, the main symptom of this type of weight loss is that a person feels healthier.
Unintended weight loss is a cause for concern. In this setting, the healthcare provider will want to know more information, such as:
How much weight has been lost?
When did the weight loss start?
Has the person's appetite or thirst level changed?
Has the person's diet changed?
Has the person's activity level changed?
Has there been a change in the person's bladder or bowel habits?
Has the person's mood changed?
What medicines or drugs is the person taking?
What other medical conditions does the person have?
Are there any other symptoms, such as fever or weakness?
Diagnosis & Tests
How is the condition diagnosed?
Diagnosis of the cause of weight loss starts with a medical history and a physical exam. This may be all that is needed to figure out the cause in some cases. In other cases, further tests are needed. Blood and urine tests may be ordered to diagnose underlying health problems.
X-ray tests may be done, such as a chest X-ray to look for heart or lung disease. A special X-ray test, called a CT scan, can look for cancer of the pancreas or liver.
Prevention & Expectations
What can be done to prevent the condition?
For unintended weight loss, prevention is related to the cause. Avoiding the drugs that cause weight loss could prevent those cases due to drugs. Practicing safer sex could prevent many cases due to HIV infection. Many cases of unintended weight loss cannot be prevented.
What are the long-term effects of the condition?
Intentional weight loss from a healthy diet and exercise decreases the risk of:
blood clots, such as deep venous thromboses
cancer
death
diabetes
gallstones
heart disease
high blood pressure
osteoarthritis, which is also called wear and tear arthritis, the most common type of arthritis
varicose veins, which are enlarged veins often seen in the legs
The long-term effects of unintentional weight loss are related to the cause. Cancer, diabetes, HIV, and severe heart, liver, or kidney disease are common causes of death. Many people who abuse drugs have long-term effects related to social, legal, and psychological problems from the drug abuse.
What are the risks to others?
Weight loss is not contagious. If infection is the cause of unintended weight loss, however, the infection may be contagious. HIV, for example, can be sexually transmitted. Tuberculosis can be spread through respiratory secretions.
Treatment & Monitoring
What are the treatments for the condition?
Weight management plans are helpful for obese or overweight people who want to lose weight.
Treatment for unintended weight loss is directed at the cause. For example, a person with diabetes may need insulin injections or other medicines to control his or her blood glucose levels. Someone who is abusing drugs may need to enter a rehabilitation program. An individual with an infection may need antibiotics. A person with cancer may need surgery, chemotherapy, or radiation therapy.
What are the side effects of the treatments?
Side effects depend on the treatment used for weight loss. Medicines may cause allergic reactions or stomach upset. Surgery carries a risk of bleeding, infection, and allergic reactions to anesthesia.
What happens after treatment for the condition?
A person who loses weight from diet and exercise often feels healthier and happier. Someone with unintentional weight loss may be cured by treatment, such a person with depression. Others may die, such as those with advanced cancer, HIV, or severe liver disease.
How is the condition monitored?
Weight can be monitored at home and at every visit to the healthcare provider. Further monitoring is related to the cause. For example, a person with diabetes needs frequent blood tests to monitor his or her blood glucose level. Any new or worsening symptoms should be reported to the healthcare provider.
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