12 Unexplained Weight loss Causes and Symptoms

Not all weight loss is a sign of serious diseases. It can also occur after a difficult or life-changing event. Unexplained weight loss, however, may be a symptom of one of these medical conditions.

1. Type 1 Diabetes

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Type 1 diabetes is can also cause unexplained weight loss. If you have type 1 diabetes, the immune system will destroy insulin-producing cells in your pancreas. Therefore, the body can not use glucose for energy without insulin. Usually, it causes high glucose in the blood. The kidneys use urine to absorb excess glucose. When the body leaves sugar, so do calories.


  • Increased thirst
  • Frequent urination
  • Bed-wetting in children who previously didn’t wet the bed during the night
  • Extreme hunger
  • Unintended weight loss
  • Irritability and other mood changes
  • Fatigue and weakness
  • Blurred vision

Type 1 diabetes treatment involves glucose, tracking blood sugar, diet changes, and exercise.

2. Loss of Lean Muscle Mass

Loss of a muscle or muscle loss can lead to unexplained weight loss. However, the major symptom is the weakening of the muscle. One of your arms may look even smaller than the other. The body is made of fat- and fat-free mass, including bone, muscle, and water. Therefore, you will lose weight when you lose your muscle.


  • Frequent falls
  • Difficulty rising from a lying or sitting up position
  • Trouble running and jumping
  • Waddling gait
  • Walking on the toes
  • Large calf muscles
  • Muscle pain and stiffness
  • Learning disabilities

If you don’t train your muscles for a while, this can happen. It’s most common in people who do not have physical activity.

3. Depression

Unexplained weight loss can be a side effect of depression, which for at least two weeks is described as feeling sad, depressed, or empty. Such feelings interfere with everyday activities. However, depression affects the same parts of the brain that regulate appetite. This may cause poor appetite and weight loss. Depression can increase appetite in some people.


  • Feelings of sadness, tearfulness, emptiness or hopelessness
  • Angry outbursts, irritability or frustration, even over small matters
  • Loss of interest or pleasure in most or all normal activities, such as sex, hobbies or sports
  • Sleep disturbances, including insomnia or sleeping too much
  • Tiredness and lack of energy, so even slight tasks take extra effort
  • Reduced appetite and weight loss or increased cravings for food and weight gain
  • Anxiety, agitation or restlessness
  • Slowed thinking, speaking or body movements
  • Feelings of worthlessness or guilt, fixating on past failures or self-blame
  • Trouble thinking, concentrating, making decisions, and remembering things
  • Frequent or recurrent thoughts of death, suicidal thoughts, suicide attempts or suicide
  • Unexplained physical problems, such as back pain or headaches

However, the signs vary from individual to individual. Depression symptoms include Behavioral therapy psychotherapy and they use antidepressants for depression treatment.

4. Tuberculosis (TB)

Tuberculosis (TB), a contagious disease that affects the lungs, is another cause of unusual weight loss. It is caused by bacteria from Mycobacterium tuberculosis. Therefore, loss of weight and decreased appetite are signs of TB, but it is not understood why. TB spreads in the polluted air. You can be a victim of TB without getting even sick.


  • Coughing that lasts three or more weeks
  • Coughing up blood
  • Chest pain or pain with breathing or coughing
  • Unintentional weight loss
  • Fatigue
  • Fever
  • Night sweats
  • Chills
  • Loss of appetite

If you have a strong immune system, the bacteria will become inactive. That is called latent tuberculosis. They typically treat TB for six to nine months with a course of antibiotics.

5. Overactive Thyroid

If the thyroid gland releases too much thyroid hormone, hyperthyroidism or overactive thyroid hormone may also grow. Such hormones regulate many of the body’s functions, including metabolism. If your thyroid is overactive, even if you have a good appetite, you can burn calories. The consequence may be an unexplained loss of weight.


  • Unintentional weight loss
  • Rapid heartbeat
  • Irregular heartbeat
  • Pounding of your heart
  • Increased appetite
  • Nervousness
  • anxiety
  • irritability
  • Tremor
  • Sweating
  • Changes in menstrual patterns
  • Increased sensitivity to heat
  • Changes in bowel patterns
  • An enlarged thyroid gland
  • Fatigue, muscle weakness
  • Difficulty sleeping
  • Skin thinning
  • Fine, brittle hair

Hyperthyroidism diagnosis depends on your age and seriousness of the condition. Therefore, they treat it with anti-thyroid medications, radioactive iodine, beta-blockers, or surgery.

6. Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease that leads to inflammation that causes the immune system to attack the lining of your joints. Therefore, inflammation can speed up metabolism and reduce body weight. RA symptoms also include swelling of the joints and discomfort. On both sides of your body, this affects the same joints. If you have RA, and you don’t move for an hour or more, your joints may feel stiff.


  • Tender
  • Warm
  • Swollen joints
  • Joint stiffness
  • Fatigue
  • Fever
  • Loss of appetite
  • Unexplained weight loss

RA diagnosis begins with medication. Medicines include kinase inhibitors associated with disease-change antirheumatic drugs, corticosteroids, biologics, and Janus.

Related: Pain Management Exercises For RA Patients.

7. Cancer

Cancer is the general term for diseases that cause rapid division and spread of abnormal cells. One of the first symptoms may be an unexplained weight loss of 10 pounds or more, according to the American Cancer Society. This is normal in pancreatic, lung, and stomach cancers. Cancer causes inflammation to increase. Therefore, it causes muscle wasting and disrupts hormones that control the appetite.

An increasing tumor may also increase the expenditure of your resting energy (REE) or the amount of energy your body burns at rest. Many conditions may cause such effects. Sometimes, there are no signs or symptoms that cause cancer.


  • Persistent cough or blood-tinged saliva
  • A change in bowel habits
  • Blood in the stool
  • Unexplained anemia
  • Breast lump
  • Lumps in the testicles
  • A change in urination
  • Blood in the urine
  • Hoarseness
  • Persistent lumps or swollen glands
  • Obvious change in a wart
  • Indigestion or difficulty swallowing
  • Unusual vaginal bleeding or discharge
  • Unexpected weight loss, night sweats, or fever
  • Continued itching in the anal or genital area
  • Nonhealing sores
  • Heavy Headaches
  • Back pain, pelvic pain, bloating, or indigestion

Treatment depends on the cancer type. Operation radiation therapy, chemotherapy, and immunotherapy are common therapies.

8. HIV

HIV targets the T-cells of the immune. It makes the battle against infections hard. However, HIV can lead to immunodeficiency syndrome (AIDS) if left untreated. These advanced forms also cause weight loss. Therefore, symptoms such as sore throat, sores in the mouth, and tiredness can make eating unpleasant. The risk of secondary infections is also raised by HIV, which increases REE. HIV symptoms depend on the individual and infection levels.


  • Fever
  • Headache
  • Muscle aches
  • Joint pain
  • Rash
  • Sore throat
  • painful mouth sores
  • Swollen lymph glands on the neck
  • Unexplained weight loss

Antiretroviral therapy is used to cure HIV to prevent the disease from spreading and may increase weight loss.

9. Inflammatory Bowel Disease

A symptom of inflammatory bowel disease (IBD) can also lead to weight loss. IBD is a term that includes a variety of chronic digestive tract inflammatory disorders. Crohn’s disease and ulcerative colitis are the two most common types. Therefore, IBD’s chronic inflammation places the body in a catabolic state, meaning that food is being used up.

IBD also interferes with ghrelin, the hormone of appetite, and leptin, the hormone of satiety. This leads to reduced loss of appetite and weight. Some foods also can trigger these symptoms. You may be unwilling to eat if you have IBD.


  • Diarrhea
  • Fever
  • fatigue
  • Abdominal pain
  • Blood on your stool
  • Reduced appetite
  • Unexplained weight loss

IBD diagnosis involves dietary aid, medicine, and surgery sometimes.

10. COPD

Recurrent lung disease is a chronic obstructive pulmonary disease (COPD). It includes chronic bronchitis and emphysema. However, most people have both of them with COPD. Therefore, emphysema affects the lungs’ air sacs, making breathing difficult. In addition, chronic bronchitis causes the airways to become inflamed, forcing air into your lungs.

This usually creates problems with mucus, coughing, and breathing. As a result, COPD can cause weight loss in later stages. A person with COPD may need 10 times more calories to breathe than a person without COPD, according to the Cleveland Clinic.

It may also feel uncomfortable at the same time as feeding or breathing. However, smoking is the major cause of COPD. In addition, long-term irritant exposure such as air pollution and dust may also result in COPD.


  • Shortness of breath
  • Wheezing
  • Chest tightness
  • A chronic cough produces mucus (sputum)
  • The blueness of the lips and fingernail
  • Frequent respiratory infections
  • Lack of energy
  • Swelling in ankles, feet or legs
  • Unexplained weight loss

Treatment involves drugs such as bronchodilators and lung treatments such as oxygen therapy.

Related: Exercise With COPD Disease.

11. Infective Endocarditis

Endocarditis causes the inner lining or endocardium of your heart to be inflamed. Usually, this happens when germs enter the bloodstream and accumulate in your chest. Therefore, most endocarditis patients have a fever. A low appetite may follow this. In addition, it also increases metabolism and burns fat, causing weight loss. Among healthy hearts, endocarditis is rare.

Individuals with damaged heart valves, artificial heart valves, and congenital heart problems are more likely to be affected.


  • Flu, fever, and chills
  • Fatigue
  • Aching joints and muscles
  • Night sweats
  • Shortness of breath
  • Chest pain
  • Swelling in your feet
  • Unexplained weight loss

They use antibiotics and chemotherapy in the diagnosis of endocarditis.

12. Addison’s Disease

Addison’s disease occurs when the adrenal glands are damaged by the immune system. In addition, the adrenal glands, including cortisol and aldosterone, can not produce enough hormones. Cortisol regulates many functions, including metabolism and appetite. Therefore, low cortisol levels can cause poor appetite and loss of weight.


  • Fatigue
  • Decreased appetite
  • Darkening of skin
  • Low blood pressure
  • Salt craving
  • Low blood sugar
  • Nausea, diarrhea or vomiting
  • Abdominal pain
  • Muscle or joint pains
  • Irritability
  • Depression or other behavioral symptoms
  • Body hair loss
  • Sexual dysfunction in women
  • Unexplained weight loss

They include medications that will control the adrenal gland.

Bottom Line

The changes in your body weight are natural. But if you lose weight without changing your habits, there might be something else going on. However, visit your doctor if you experience unexplained weight loss in 6 to 12 months or if you note any of the above symptoms.


Type 1 diabetes. Mayo Clinic.

Depression (major depressive disorder). Mayo Clinic.

Tuberculosis. Mayo Clinic.

18 Common Cancer Symptoms and SignswebMD.

HIV/AIDS. Mayo Clinic.

Inflammatory bowel disease (IBD). Mayo Clinic.

COPD. Mayo Clinic.

Endocarditis. Mayo Clinic.

Addison’s disease. Mayo Clinic.

Nutritional Guidelines for People with COPD. Cleveland Clinic.

Signs and Symptoms of Cancer. American Cancer Society.

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Naeem Durrani BSchttps://defatx.com/
I am a retired pharmacist, nutrition expert, journalist, and more. My interests include medical research, and the scientific evidence around effective wellness practices, which empower people to transform their lives.

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