Unexplained Weight Loss: What You Need to Know

There has always been a surrounding stigma towards weight gain as well as a diet culture that praises weight loss and skinny physiques, but what about those who have unintentionally dropped pounds in a short amount of time?

Just as excessive weight gain can be alarming, so can excessive weight loss, especially when diet and exercise have remained untouched and unaltered in the person’s routine.

What is Unexplained Weight Loss?

Unexplained weight loss (also known as unintentional weight loss) happens when a person loses more than 5 percent of body weight within a span of 6 to 12 months without the intention of dropping it. Basically it happens when a person significantly drops a lot of weight without even trying.

Although it may seem like a miracle or a blessing in disguise to unintentionally lose that much weight, it is always best to consult a doctor when you come across an event like this. Your body weight is an essential factor to be considered in your life, and is usually correlated with body fat. However, it is not just body fat that comprises a person’s weight.

A person’s body mass is divided among four components: body fat, muscle, bone, and water. All are equally important and essential for the regular daily functions and systems of the body. When a person drops a significant amount of weight, that indicates a major depletion of one or more of the above components, which may alter and have negative repercussions towards the body.

Furthermore, the body is always aiming to maintain a state of equilibrium and balance, so if it does experience a significant loss of weight, it most likely may be due to certain underlying health conditions that need to be assessed by a professional health practitioner.

General Causes of Unexplained Weight Loss

Muscle Atrophy

Muscle Atrophy, otherwise known as muscle loss, is quite a common factor in weight loss. 30 to 50 percent of a person’s entire body mass is made up of muscle. Thus, a significant loss in muscle makes an evident contribution to a person’s weight loss.

A person may experience muscle atrophy after reduced physical activity, or due to certain conditions that affect the muscular system of the body such as osteoarthritis, nerve damage, osteoporosis, rheumatoid arthritis, and many more. Other mundane causes such as aging and injuries may also contribute to muscle loss.

Increase in Metabolism 

A significant increase in metabolism may lead to unintentional weight loss. This is because a faster metabolism also means quicker burning of calories. The increase in metabolism can be attributed to many responses in the body.

One of these responses is when a body undergoes a fever. A fever usually occurs because the body is trying to fight off a colony of bacteria or viruses. This causes the immune system to work extra hard, and prompts the metabolism to quicken to ensure a constant adequate supply of the necessary energy and nutrients.

Another response of the body that quickens the metabolism is a speedy heart rate. A faster heart rate quickens the blood flow, causing a speed-up in the body’s overall systems (also known as metabolism).

Psychological Problems

Psychological problems such as depression and anxiety can be a huge contributor towards weight loss. Even though these problems primarily target the brain, a domino effect may occur causing the physical attribute of the body to be affected as well. However, the symptoms of these psychological problems differ for everybody, so some may experience weight loss due to this while some may experience weight gain.

Weight loss due to depression and anxiety may be linked to the possibility of appetite-related symptoms. Some people with this sickness experience a loss of appetite and/or constant sadness that leads to lack of motivation towards physical activity and food consumption. On the other hand, some people with severe cases of anxiety may often experience palpitations or episodes of a speedy heart rate, which contributes to the quickening of metabolism.

What Conditions do Cause Unexplained Weight Loss?

1. Hyperthyroidism 

Hyperthyroidism, also known as overactive thyroid, is a health condition that affects the thyroid gland, where it produces too much of the thyroid hormone.

The thyroid hormone is an important part of the body as it regulates body temperature and is an essential hormone in digestion and metabolism. It’s primary responsibility is to turn glucose into energy. Thus, the overproduction of the said hormone causes the overburn of calories, which eventually leads to significant weight loss.

Additionally, when the body converts too much sugar into energy, it results in a quickening of the metabolism, causing an increase in heart rate, fatigue, trouble sleeping, shakiness, anxiety, etc.

2. Type 1 Diabetes 

Diabetes is a condition that restrains the pancreas from producing the hormone insulin. Insulin is one of the most important hormones for energy consumption, as it is also responsible for converting glucose (or blood sugar) into energy as well as regulating blood sugar levels in the body.

In the absence of insulin, the body’s glucose renders unused, and is then excreted by the kidneys in the form of urine. Naturally, since calories are in the form of glucose in the body, the excretion of glucose eventually results in weight loss.

Since the body isn’t consuming any energy at this state, this condition also results in fatigue, dehydration, and excessive hunger; and since the body is frequently releasing glucose in the form of urine, a significant indicator for type 1 diabetes is frequent urination.

Therefore, it is important for those with this condition to constantly monitor blood sugar, and have regular insulin shots, to ensure that the energy from the food you eat does not go to waste.

3. Tuberculosis

Tuberculosis (TB) is a bacterial infection that most commonly targets the lungs, but it may affect or spread to other parts of the body as well such as the abdomen, glands, bones, and nervous system.

Tuberculosis can be linked to unexpected weight loss due to its symptoms. TB is usually identified by having a loss of appetite, persistent coughing, fatigue, fever, swellings, and many more. All of which contribute negatively to a person’s desire to eat and consume food, eventually causing weight loss.

Most people that are affected with Tuberculosis also struggle with malnutrition, or may experience malnutrition due to the said disease. This may also contribute to the reduction of body mass because of excessive muscle loss.

4. Heart Conditions

Heart conditions such as Congestive Heart Failure (CHF) may lead to unintentional weight loss or Cardiac Cachexia (severe weight loss due to heart complications).

Congestive Heart Failure (CHF) is a heart disease that prevents the heart from either pumping with adequate force or pumping with enough blood. This causes abnormalities of the blood circulation in the body, affecting the body’s systems and metabolism due to an inadequate and abnormal supply of blood.

One scenario of this that contributes to unintentional weight loss is when the digestive system experiences abnormalities in blood supply and causes nausea and early fullness. This is because recycled blood as well as the lack of blood supply causes inflammation of the intestines, preventing it from digesting food and absorbing nutrients properly. This also leads to a decrease in appetite, nausea, and fatigue.

Furthermore, when the body experiences a lack of blood, the heart naturally responds through a quickening in heartbeat as it tries to catch up to the needed blood supply. A faster heart rate then leads to a quicker metabolism, thus, burning calories quicker.

Due to nausea and fatigue caused by CHF, a person with this disease may also experience weight loss because of a decline in physical activity, reducing muscle action. This will eventually cause weight loss because of muscle loss.

Another heart condition that may lead to weight loss is Endocarditis. This occurs when the endocardium (inner lining of the heart) is inflamed due to the accumulation of bacteria in the heart by means of the blood. An inflamed heart often results in a fever, as the body’s immune system tries to combat the bacterial infection. Along with an increased temperature and an overworking immune system also comes an increase in metabolism, causing you to burn excess calories quicker. This eventually leads to weight loss.


Human Immunodeficiency Virus or HIV is a type of virus that attacks the immune system, weakening its functions and causing Acquired Immunodeficiency Syndrome or AIDS. Because this sickness attacks the immune system, a person with AIDS will be more vulnerable to infections.

The body’s natural response to HIV is to combat it using the immune system. As this infection is viral, the immune system will have to work harder in order to overcome this virus. This leads to a faster burn and consumption of calories and eventually evident weight loss. Another symptom to be observed in relation to this is fatigue. Because the body is working harder to combat the virus, an infected person may experience overfatigue, reducing the person’s physical activity, and eventually causing muscle loss which is another component of body mass.

Weight loss as a symptom of HIV may also be due to how and where the virus attacks in your body. This virus has a tendency to disrupt hormones, including the ones that are responsible for regulating digestion, metabolism, as well as appetite. With that being said, people affected with HIV will most likely experience unintentional weight loss due to their loss in appetite, slower metabolism, and other gastrointestinal problems such as diarrhea.

6. Addison’s Disease

Addison’s disease is a condition that affects the outer layer of the adrenal gland (the gland that produces hormones that are responsible for metabolism, immune system, blood pressure, etc.) causing it to produce significantly less hormones that the body needs.

One important hormone that may be affected by Addison’s disease is the Cortisol hormone (responsible for regulating metabolism and appetite). Inadequate levels of Cortisol can be attributed towards a decrease in appetite, which often leads to weight loss.

Another symptom of Addison’s disease is over fatigue and consistent vomiting. Thus, most people who contract Addison’s disease may also struggle with anorexia, struggling to maintain calorie intake and reduced muscle mass due to less physical activity.

7. Cancer

Cancer is a disease notorious for having no cure, and it is capable of affecting any and every organ of your body. It is diagnosed by identifying abnormal overgrowth of the cells called tumors, in which they are distinguished as cancerous when they are malignant (are able to spread towards other areas of the body). Benign tumors (tumors that don’t spread) on the other hand, are typically harmless and are not considered cancerous but still require medical attention.

One of the most distinct early symptoms for certain types of cancer is unexplained weight loss. Cancer that affects organs responsible for metabolism and digestion are often bound to have a drastic effect towards a person’s body weight.

Cancers such as Pancreatic Cancer, Lung Cancer, Cancer of the Esophagus, and Gastrointestinal Cancer are some types of cancer that evidently show symptoms of unexplained weight loss. This is because the cancer is capable of affecting the normal functions of the affected organs, which leads to abnormalities in the body’s systems and eventually weight loss.

The disease of cancer itself isn’t the only culprit for weight loss. Treatments used to cure cancer such as Radiation and Chemotherapy may also lead to unexplained weight loss. Cancer treatments usually cause mouth sores, nausea, vomiting, fatigue, and other symptoms that affect appetite. Thus, discouraging the person to eat and consume food, resulting in weight loss.

8. Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is a disease that affects the lungs. Diseases such as Emphysema and  Chronic Bronchitis are also attributed to COPD causing breathing problems and frequent coughing.

COPD can cause weight loss due to a variety of reasons. One symptom of COPD is the loss of appetite, prompting the body to withdraw energy from muscles and fat because of the lack of calorie and nutrient intake. Another symptom of COPD is difficulty in breathing. When the body has trouble breathing, the body tries to catch up by exerting more effort to breathe, increasing the metabolism and consuming excess calories.

9. Arthritis

Arthritis, specifically Rheumatoid Arthritis (RA) is an autoimmune disease that causes inflammation of the joints. This is typically diagnosed when a person feels swelling and pain on or around the joints.

People with RA will most likely experience weight loss as well due to its symptoms. Some of the symptoms of RA include: loss of appetite, pain in the joints, fatigue, vomiting, etc. Each of these symptoms provide adequate contribution as to why a person with RA will most likely lose weight.

Loss of appetite discourages food consumption, thus limiting calorie intake which eventually leads to weight loss. Constant vomiting also prohibits the body from digesting and converting food into energy, defeating the purpose of consuming food as a source of fuel. Frequent pain in the joints as well as fatigue also discourages a person from conducting physical activity, limiting muscle movement and action. Because of this, a person with RA may lose weight due to a loss in muscle mass.

What to Do When I Notice Unexplained Weight Loss?

Unexplained weight loss can happen to anybody, but is more likely to occur to people above the age of 65. Nevertheless, it is always safest to always be on the lookout in case it may happen to you.

The most important thing to do when you notice unexplained weight loss is to consult your doctor. Seeking the opinion of a professional is always the safest way to go. Upon consultation, the doctor will most likely ask lifestyle and health related questions such as:

  • How much weight have you lost?
  • When did you start to notice a drop in weight?
  • How often do you exercise?
  • Do you have a history of chronic illnesses?
  • What does your diet look like?
  • Are you experiencing any psychological problems?

Treatment for the unexplained weight loss may depend on whatever your doctor diagnoses. Regardless, it is always important to maintain a balanced and fit lifestyle to strengthen your immune system and reduce the risk of contracting any of the above mentioned conditions that may allow unexplained weight loss to happen to you.


  1. https://www.healthline.com/health/unexplained-weight-loss#:~:text=Unexplained%20weight%20loss%2C%20or%20losing,within%206%20to%2012%20months
  2. https://my.clevelandclinic.org/health/diseases/17770-unexplained-weight-loss
  3. https://www.mayoclinic.org/symptoms/unexplained-weight-loss/basics/definition/sym-20050700
  4. https://www.medicalnewstoday.com/articles/326417
  5. https://www.healthline.com/health/cancer-weight-loss-how-fast#cancer-treatment-weight-loss
  6. https://www.cancer.gov/about-cancer/understanding/what-is-cancer
  7. https://tbfacts.org/nutrition-tb/#:~:text=Most%20individuals%20with%20active%20TB,body%27s%20ability%20to%20fight%20disease
  8. https://www.nhs.uk/conditions/tuberculosis-tb/
  9. https://www.webmd.com/hiv-aids/guide/aids-wasting-syndrome
  10. https://www.uofmhealth.org/health-library/tx4124abc
  11. https://www.physio-pedia.com/Addison%27s_Disease
  12. https://www.medicalnewstoday.com/articles/copd-and-weight-loss#risks
  13. https://www.medicalnewstoday.com/articles/323614#effects-of-weight-loss-with-ra
  14. https://creakyjoints.org/about-arthritis/rheumatoid-arthritis/ra-healthy-living/weight-loss-rheumatoid-arthritis/
We will be happy to hear your thoughts

Leave a reply