Understanding The Underlying Factors Of Unintentional Weight Loss

Understanding The Underlying Factors Of Unintentional Weight LossUnexplained or unintentional weight loss, while initially perceived as a positive change by some individuals, warrants a closer examination of its potential causes. It is crucial to investigate the reasons behind this type of weight loss, as it can be indicative of an underlying medical condition. The causes of unintentional weight loss can range from thyroid disorders to various forms of cancer.

Medical evaluations have shown that at least 72% of individuals experiencing unexpected weight loss are found to have an underlying condition. Therefore, it is essential to engage in a conversation with your healthcare provider if you are facing unexplained weight loss.

This article aims to delve into the realm of unexpected weight loss, discussing the possible reasons behind it and shedding light on the collaborative process between you and your healthcare provider to identify and treat the underlying cause.

Definition of Unintentional Weight Loss

Unintentional weight loss refers to the involuntary reduction of body weight by at least 5% within a period of six to twelve months. For instance, in a 200-pound man, this would translate to a 10-pound loss, while a 130-pound woman may experience a weight reduction of 6 to 7 pounds.

Weight loss occurs without any deliberate efforts to lose weight, such as calorie restriction or starting an exercise regimen.

When to Seek Medical Attention

Identifying the underlying causes of unintentional weight loss can be challenging, particularly during the early stages of certain conditions. Sometimes, a series of blood tests or imaging studies like X-rays are necessary to determine the root cause.

It is crucial to consult a healthcare provider if you are experiencing a weight loss of 5% to 10% without intentional efforts, even if you believe there might be an explanation for it. Continuously inquire about the reasons behind your weight loss until you feel confident in understanding them.


Numerous factors can contribute to unexplained weight loss, some of which may be serious. In adults who do not reside in nursing homes or other care facilities, the most common causes include cancer, digestive tract disorders like inflammatory bowel disease, and mental health-related issues such as depression.

Approximately 40% of individuals diagnosed with cancer reported experiencing weight loss at the time of their diagnosis. A study conducted in 2018 identified this weight loss as the second-strongest predictor for certain types of cancer.


Weight loss can serve as an early indicator of blood-related cancers like leukemia and lymphoma, as well as solid tumors such as lung cancer (especially adenocarcinoma of the lung), colon cancer, ovarian cancer, and pancreatic cancer. Weight loss may also occur when an early-stage tumor, such as breast cancer, recurs.


Diabetes is categorized into Type 1, an autoimmune disease, and Type 2, which often develops later in life when the body cannot produce or process insulin effectively. Unexplained weight loss can occur in both types, although it is more commonly associated with Type 1 diabetes.


Hyperthyroidism refers to a condition where the thyroid gland in the neck becomes overactive. It can be caused by various conditions, including autoimmune disorders like Graves’ disease, which is the leading cause of hyperthyroidism in the United States. Iodine exposure, medication errors, and pregnancy can also contribute to an overactive thyroid. Hyperthyroidism accelerates metabolism, leading to weight loss.

Muscle Loss

Weight loss may be linked to the loss of comparatively heavy muscle tissue, referred to as muscle atrophy or muscle wasting. This is particularly evident in individuals with cancer or those diagnosed with HIV/AIDS, a condition known as cachexia, which can be fatal and accounts for approximately 25% of cancer-related deaths.


Depression can alter eating habits, resulting in weight loss or weight gain. It affects individuals from all walks of life, and roughly one in every six people will experience depression at some point in their lives.

Addison’s Disease

Addison’s disease is an endocrine disorder associated with problems in the adrenal glands located above each kidney. These glands produce crucial hormones like cortisol. The absence of these hormones in Addison’s disease can cause weight loss, fatigue, and other symptoms.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is primarily known for causing joint pain and damage, but it can also lead to muscle wasting and weight loss referred to as rheumatoid cachexia. RA may be linked to inflammation of the digestive system and gastrointestinal diseases, which can contribute to unintentional weight loss.

Other Causes

There are several other causes of unintentional weight loss that should be considered:

  1. Hypothyroidism: This condition occurs when the thyroid gland is underactive and can sometimes contribute to weight loss, although it is more commonly associated with weight gain.
  2. Infections: Viral, bacterial, and parasitic infections, such as HIV/AIDS, tuberculosis, and endocarditis (infection of the heart valves), can lead to weight loss.
  3. Intestinal problems: Conditions like peptic ulcer disease, celiac disease, Crohn’s disease, ulcerative colitis, and pancreatitis can cause weight loss due to digestive issues.
  4. Heart failure: Loss of muscle mass associated with weight loss can be seen in individuals with heart failure.
  5. Kidney failure: Poor appetite and nausea, along with fluid retention issues, can contribute to weight loss in individuals with kidney failure.
  6. Chronic obstructive pulmonary disease (COPD): Various conditions like emphysema, bronchiectasis, and chronic bronchitis, which fall under the umbrella of COPD, can lead to unintentional weight loss.
  7. Oral concerns: Dental problems such as gum disease, tooth decay, mouth sores, or the presence of braces can affect eating and result in weight loss.
  8. Smoking: Weight loss among smokers is often associated with metabolic changes and altered absorption of nutrients.
  9. Eating disorders: Conditions like anorexia nervosa and bulimia can cause significant weight loss, and individuals struggling with these disorders may not recognize the significance of their weight loss.
  10. Poor nutrition: Inadequate food choices or limited access to sufficient food can lead to unintentional weight loss.
  11. Medications: Many medications can cause weight loss directly or indirectly, either through their effects on metabolism or by causing nausea and loss of appetite.
  12. Drug abuse: Substance abuse involving drugs like methamphetamine, as well as the misuse of prescription medications like Adderall or over-the-counter drugs like laxatives, can result in weight loss.
  13. Neurological conditions: Certain neurological conditions such as Parkinson’s disease and Alzheimer’s disease can be associated with unintentional weight loss.

Weight Loss Causes in Men and Women

Both men and women can experience unintentional weight loss. However, certain conditions may be more prevalent in one gender than the other. For example, autoimmune disorders like rheumatoid arthritis (RA) and Graves’ disease are more commonly found in women. Eating disorders and depression also tend to affect women more frequently, as does weight loss related to pregnancy. On the other hand, men may face risks associated with cancer cachexia, digestive problems, and infections like endocarditis.


When experiencing unintentional weight loss, it is essential to provide your healthcare provider with a detailed medical history. Along with a physical examination, this information will help them identify risk factors and narrow down the potential underlying medical conditions.

Your healthcare provider may ask you questions such as:

  1. When did you first notice the weight loss?
  2. Have you made any changes to your diet or exercise routine?
  3. Are you experiencing other symptoms like shortness of breath or excessive thirst?
  4. Have you undergone any screening tests, such as a colonoscopy, and if so, what were the results?
  5. Have you been feeling depressed or stressed lately?
  6. Do you have any dental issues that make eating difficult?
  7. Are there any known hereditary illnesses in your family?

Tests and Labs

The specific blood tests ordered by your healthcare provider will depend on various factors, including your symptoms. Commonly performed tests include:

  1. Complete blood count (CBC): This test can detect infections, anemia, and other abnormalities.
  1. Thyroid panel: Assessing Tests and Labs
  2. Liver function tests: These tests evaluate the function of the liver and can help identify any liver-related causes of weight loss.
  3. Kidney function tests: These tests assess kidney function and can indicate if kidney problems are contributing to weight loss.
  4. Blood sugar (glucose) test: This test measures blood sugar levels and helps detect conditions like diabetes that may be associated with weight loss.
  5. Urinalysis: Analyzing urine samples can provide insights into various underlying conditions.
  6. Tests for inflammation: Non-specific tests like the sedimentation rate (sed rate) and C-reactive protein (CRP) can indicate the presence of inflammation.
  7. Electrolyte levels: Monitoring sodium, potassium, and calcium levels can offer clues about potential underlying issues.


In some cases, additional procedures may be necessary to further investigate the causes of unintentional weight loss. These procedures may include:

  1. Endoscopy: Procedures like upper gastrointestinal (GI) endoscopy or colonoscopy can examine the digestive tract for any abnormalities that may be contributing to weight loss.
  2. Echocardiogram: An echocardiogram, which is an ultrasound of the heart, can help diagnose various conditions, including infectious endocarditis.

Imaging Studies

Imaging tests may be recommended to obtain detailed images of specific areas of the body. These can include:

  1. Chest X-ray: While a chest X-ray can miss certain conditions like lung cancer, it can still provide valuable information.
  2. Computerized tomography (CT) scan: CT scans of the chest or abdomen can help identify potential causes of weight loss.
  3. Magnetic resonance imaging (MRI): MRIs can provide detailed images of organs and tissues and may be used to investigate potential causes of weight loss.
  4. Positron emission tomography (PET) scan: PET scans can detect signs of cancer metastasis, aiding in the diagnosis of underlying cancers.


Unintentional weight loss is not only important as an indicator of an underlying cause but also due to its impact on overall health. Unexplained and unintentional weight loss can complicate the treatment and recovery of various conditions, including coronary artery disease.

Many of the underlying causes of unintentional weight loss are serious conditions on their own. Seeking medical attention, undergoing necessary tests, and receiving appropriate treatment can lead to better outcomes. Additionally, weight loss itself is associated with higher mortality rates and a lower quality of life in individuals with these illnesses.


The treatment of unintentional weight loss depends on identifying and addressing the underlying causes. It is highly likely that there is an underlying cause for the weight loss, and it is important to address it. While treating the identified cause, it is crucial to also address the weight loss itself. If diagnosed with cancer, considering a palliative care consultation can be beneficial, as palliative care teams are skilled at addressing concerns unrelated to cancer treatment, such as unintentional weight loss.


Unexplained weight loss should not be ignored, as it often serves as a clue to an underlying illness that requires diagnosis and treatment. Consulting a healthcare provider is crucial for identifying the cause of weight loss and addressing both the underlying condition and the weight loss itself.

Frequently Asked Questions about Unintentional Weight Loss

  1. What is the most common reason for unintentional weight loss? The most common reason for unintentional weight loss varies depending on age. Among older individuals, cancer is often the leading cause. Nonmalignant causes, such as medication-related diminished appetite, are more common among those aged 65 and older. However, there are cases where the cause of unintentional weight loss remains unexplained.
  2. When should I be concerned if I start losing weight without trying? Any amount of weight loss can be a potential concern. However, unintentional weight loss is typically defined as a loss of 10 pounds or 5% of total body weight within six to twelve months, especially in individuals aged 65 and older, where the condition is more prevalent.
  3. Which types of cancer most commonly cause weight loss? Weight loss associated with cancer, known as cachexia, is commonly seen in pancreatic cancer, stomach (gastric) cancer, lung cancer (especially adenocarcinoma), esophageal cancer, colon cancer, and head and neck cancers.
  4. How can I deal with appetite loss due to unintentional weight loss? If you are experiencing appetite loss along with unintentional weight loss, it is essential to consult your healthcare provider. They can help identify and address the underlying cause and provide guidance on managing appetite and maintaining proper nutrition.
  5. Are there specific risk factors for unintentional weight loss? While unintentional weight loss can affect anyone, certain risk factors may increase the likelihood. These include older age, chronic illnesses, underlying medical conditions like cancer or autoimmune disorders, and mental health conditions such as depression.
  6. How can I determine the cause of my unintentional weight loss? Diagnosing the cause of unintentional weight loss requires a thorough medical evaluation. Your healthcare provider will review your medical history, conduct a physical examination, and order appropriate tests and screenings based on your symptoms and risk factors. It may involve blood tests, imaging studies, endoscopic procedures, and consultations with specialists.
  7. Is unintentional weight loss always a sign of a serious condition? While unintentional weight loss can indicate underlying health issues, it does not necessarily mean that it is always a sign of a serious condition. However, it should not be ignored, and it is important to consult with a healthcare provider for proper evaluation and diagnosis.
  8. Can unintentional weight loss be reversed? The potential for reversing unintentional weight loss depends on identifying and addressing the underlying cause. With proper diagnosis and treatment, weight loss may be managed or resolved. However, the approach and outcomes can vary based on the specific underlying condition.
  9. Should I be concerned about unintentional weight loss during pregnancy? Weight loss during pregnancy is not typical and may warrant medical attention. If you are pregnant and experiencing unintentional weight loss, it is important to consult your healthcare provider to ensure the well-being of both you and your baby.
  10. How can unintentional weight loss affect overall health? Unintentional weight loss can have significant impacts on overall health, including increased mortality rates and a lower quality of life. It can also complicate the treatment and recovery processes for various medical conditions, including cardiovascular diseases, cancer, and chronic illnesses. Therefore, prompt medical evaluation and appropriate management are crucial.

References & Sources

THG Urgent Care powered by Fast Track uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles.

  1. American Psychiatric Association. What Is Depression?
  2. National Institute of Diabetes and Digestive and Kidney Diseases.  Adrenal insufficiency & Addison’s disease.
  3. Perera LAM, Chopra A, Shaw AL. Approach to patients with unintentional weight lossMed Clin North Am. 2021;105(1):175-186. doi:10.1016/j.mcna.2020.08.019
  4. Bosch X, Monclús E, Escoda O, et al. Unintentional weight loss: Clinical characteristics and outcomes in a prospective cohort of 2677 patients. Wu W-CH, ed. PLoS ONE. 2017;12(4):e0175125. doi: 10.1371/journal.pone.0175125
  5. Gaddey HL, Holder KK. Unintentional Weight Loss in Older AdultsAm Fam Physician. 2021 Jul 1;104(1):34-40. PMID: 34264616.
  6. BMJ Best Practice. Evaluation of unintentional weight loss. British Medical Association.
  7. Nicholson B, Hamilton W, O’Sullivan J, Aveyard P, Hobbs F. Weight loss as a predictor of cancer in primary care: A systematic review and meta-analysisBritish Journal of General Practice. 2018;68(670):e311-e322. doi:10.3399/bjgp18X695801
  1. Perera LAM, Chopra A, Shaw AL. Approach to patients with unintentional weight lossMedical Clinics of North America. 2021;105(1):175-186. doi: 10.1016/j.mcna.2020.08.019
  1. American Thyroid Association. Graves’ disease.
  2. Siddiqui JA, Pothuraju R, Jain M, Batra SK, Nasser MW. Advances in cancer cachexia: Intersection between affected organs, mediators, and pharmacological interventionsBiochimica et Biophysica Acta (BBA) – Reviews on Cancer. 2020;1873(2):188359. doi: 10.1016/j.bbcan.2020.188359
  3. Cleveland Clinic. Unexplained Weight Loss.
  4. Lemmey AB. Rheumatoid cachexia: the undiagnosed, untreated key to restoring physical function in rheumatoid arthritis patients? Rheumatology. 2016;55(7):1149-1150. doi: 10.1093/rheumatology/kev412
  5. Bosch X, Monclús E, Escoda O, et al. Unintentional weight loss: Clinical characteristics and outcomes in a prospective cohort of 2677 patientsPLoS One. 2017;12(4):e0175125. doi:10.1371/journal.pone.0175125
  6. Gaddey HL, Holder KK. Unintentional weight loss in older adultsAm Fam Physician. 2021;104(1):34-40.

The blogs presented by TGH Urgent Care in partnership with Fast Track are not a replacement for medical care and are exclusively intended for educational purposes. The content provided here should not be construed as medical guidance. If you are encountering any symptoms, we strongly recommend that you seek an appointment with a duly qualified medical practitioner at our nearest facility.

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