Unexplained Weight Loss: Causes, Diagnosis, And Importance Of Seeking Medical Attention

Unexplained Weight Loss Causes, Diagnosis, And Importance Of Seeking Medical Attention

Unintentional weight loss, though some may view it as a welcome change, should never be ignored when seeking answers about its potential causes. This seemingly innocuous phenomenon can often be a sign of an underlying medical condition, with serious implications ranging from thyroid issues to cancer.

Medical evaluation reveals that in at least 72% of cases where weight loss occurs unexpectedly, an underlying condition is discovered. Hence, it becomes imperative for individuals experiencing unexplained weight loss to engage in a dialogue with their healthcare provider.

In this informative article presented by TGH Urgent Care powered by Fast Track, we delve into the realm of weight loss that takes us by surprise, exploring various reasons behind its occurrence and shedding light on the collaborative process between patients and healthcare providers to identify and treat the root cause.

What do you mean by Unintentional Weight Loss

Unexplained weight loss is characterized as the inadvertent reduction of at least 5% of one’s body weight within a timeframe of six to 12 months. For instance, this would translate to a 10-pound decline in a 200-pound man or a decrease of 6 to 7 pounds in a 130-pound woman. Crucially, this weight loss occurs without any deliberate effort to reduce caloric intake or engage in physical exercise for weight reduction.

When to See Your Healthcare Provider at TGH Urgent Care

Diagnosing the conditions responsible for unintentional weight loss can be challenging during the initial stages, often requiring a series of blood tests or imaging studies such as X-rays to pinpoint the underlying cause.

If you experience a weight loss of 5% to 10% without intentional effort, it is crucial to consult your healthcare provider, even if you believe there might be a reasonable explanation for the changes. Persistently asking “why” until you gain confidence in the diagnosis is essential, and do not hesitate to seek a second opinion if necessary.


Unintentional weight loss can be attributed to various factors, and some of them may have serious implications. Among adults not residing in nursing homes or care facilities, the most prevalent causes include cancer, digestive tract disorders like inflammatory bowel disease, and mental health-related issues such as depression.

A considerable number of individuals diagnosed with cancer reported experiencing weight loss, with approximately 40% citing this phenomenon at the time of diagnosis. A 2018 study further revealed that weight loss ranked as the second-strongest predictor for certain types of cancer.


The initial indication of blood-related cancers like leukemias and lymphomas, or solid tumors such as lung cancer (particularly adenocarcinoma of the lung), colon cancer, ovarian cancer, and pancreatic cancer, may manifest as weight loss. Additionally, weight loss can also occur when an early-stage tumor, such as breast cancer, reappears.


Individuals with diabetes typically fall into two main categories: Type 1 diabetes, an autoimmune disease, and Type 2 diabetes, which often develops later in life when the body struggles to produce or utilize insulin effectively. There is also a temporary form known as gestational diabetes, which occurs exclusively during pregnancy.

Unintentional weight loss can be observed in both Type 1 and Type 2 diabetes; however, it is more commonly associated with Type 1 diabetes.


Hyperthyroidism, a condition characterized by an overactive thyroid gland in the neck, can arise from various underlying conditions. These include autoimmune disorders like Graves’ disease, which stands as the predominant cause of hyperthyroidism in the United States. Other contributing factors encompass iodine exposure, medication errors, and even pregnancy, which can lead to an overactive thyroid.

The hallmark of hyperthyroidism lies in its ability to accelerate metabolism, potentially resulting in weight loss.

Muscle Loss

Weight loss can be associated with the loss of relatively dense muscle tissue, a condition referred to as muscle atrophy or muscle wasting.

This phenomenon is particularly prominent in individuals with cancer and those diagnosed with HIV/AIDS and is recognized as cachexia within these groups. The muscle loss experienced in cachexia can have severe consequences and has been identified as the primary cause of approximately 25% of cancer-related deaths.


Depression can significantly influence eating habits, resulting in either weight loss or weight gain. This mental health condition can affect individuals from diverse backgrounds, with approximately one in every six people experiencing depression at some juncture in their lives. The impact of depression on eating behaviors highlights the importance of addressing both the emotional and physical aspects of this prevalent disorder.

Addison’s Disease

Addison’s disease, classified as an endocrine disorder, arises from issues with the adrenal glands situated atop each kidney. These crucial glands are responsible for producing essential hormones, including cortisol, which act as chemical messengers within the body. In Addison’s disease, there is an insufficient production of these hormones, leading to symptoms such as weight loss, fatigue, and various other manifestations. The impact of hormone deficiency in Addison’s disease underscores the significance of proper hormone regulation for overall well-being.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is primarily recognized for its characteristic joint pain and damage. However, this autoimmune condition can also trigger muscle wasting and weight loss, a condition known as rheumatoid cachexia. The inflammatory processes associated with RA may extend to the digestive system and gastrointestinal tract, potentially contributing to unintentional and unexplained weight loss. Understanding the multifaceted impact of RA on the body can aid in addressing the diverse symptoms it presents and optimizing overall health management.

Other Causes

Unintentional weight loss can be associated with a myriad of underlying medical conditions and lifestyle factors. Here is a comprehensive list of potential causes:

  1. Hypothyroidism: This disorder results from an underactive thyroid gland and stands in contrast to hyperthyroidism. In some cases, it can also contribute to weight loss.
  2. Infections: Various infections caused by viruses, bacteria, and parasites, such as HIV/AIDS, tuberculosis, and endocarditis (infection of the heart valves), can lead to unintentional weight loss.
  3. Intestinal problems: Conditions like peptic ulcer disease, celiac disease, Crohn’s disease, ulcerative colitis, and pancreatitis can affect nutrient absorption and contribute to weight loss.
  4. Heart failure: A loss of muscle mass associated with weight loss can be a potential consequence of heart failure.
  5. Kidney failure: Poor appetite and nausea, along with alterations in fluid retention due to impaired kidney function, can lead to unintentional weight loss.
  6. Chronic obstructive pulmonary disease (COPD): Conditions like emphysema, bronchiectasis, and chronic bronchitis can impact metabolism and result in weight loss.
  7. Oral concerns: Gum disease, tooth decay, mouth sores, or the use of braces may affect eating habits and contribute to weight loss.
  8. Smoking: Weight loss in smokers can be related to changes in metabolism and the way the body processes and absorbs nutrients.
  9. Eating disorders: Both anorexia nervosa and bulimia can cause weight loss, and individuals coping with these conditions may not recognize the significance of their weight loss.
  10. Poor nutrition: Inadequate food choices or insufficient access to food can lead to unintentional weight loss.
  11. Medications: A wide range of medications may have weight loss as a consideration or side effect. Some medications can directly cause weight loss, while others may induce nausea and loss of appetite leading to weight reduction.
  12. Drug abuse: Not only street drugs like methamphetamine but also prescription medications like Adderall and over-the-counter drugs like laxatives can be abused, resulting in unintended weight loss.
  13. Neurological conditions: Conditions such as Parkinson’s disease and Alzheimer’s disease can affect eating patterns and lead to weight loss.

Recognizing these potential causes is essential for accurately identifying the underlying reasons behind unexplained weight loss and implementing appropriate interventions and treatments.

Causes of Weight Loss in Both Genders

Unintended or unexplained weight loss can affect both men and women. Certain autoimmune disorders, such as rheumatoid arthritis (RA) and Graves’ disease, are more commonly observed in women. Additionally, eating disorders and depression tend to occur more frequently in women, as does weight loss related to pregnancy.

On the other hand, men face their own set of risks concerning weight loss. They may be susceptible to conditions like cancer cachexia, digestive issues, and infections like endocarditis that can lead to unintended weight loss. Understanding the varying factors that contribute to weight loss in both genders is essential for tailored healthcare interventions and support.


If you experience unintentional weight loss, it is essential to be prepared to provide your healthcare team with a comprehensive and detailed medical history. Together with a thorough physical examination, this information enables healthcare providers to assess your risk factors and narrow down potential underlying medical conditions contributing to weight loss. Open and honest communication with your healthcare team is vital in the pursuit of an accurate diagnosis and appropriate treatment plan.

Questions Your Healthcare Provider May Ask at TGH Urgent Care

Expect to answer questions including:

1. When did you first become aware of weight loss?

2. Have there been any recent changes in your diet or exercise routine?

3. Are you experiencing any additional symptoms, such as shortness of breath or excessive thirst?

4. Have you undergone any relevant screening tests, such as a colonoscopy, and what were the findings?

5. Have you been feeling any signs of depression or experiencing elevated stress levels recently?

6. Do you have any dental issues that might be affecting your ability to eat comfortably? Are there any hereditary illnesses or medical conditions that run in your family that could be relevant to weight loss?

Tests and Labs

The blood tests ordered by your healthcare provider will be determined by various factors, including any presenting symptoms. Commonly conducted tests include:

  • Complete blood count (CBC): This test can reveal evidence of infections, anemia (a deficiency of red blood cells caused by various conditions), and other relevant information.
  • Thyroid panel: A comprehensive assessment of thyroid function to identify any abnormalities.
  • Liver function tests: These tests evaluate the health and functioning of the liver.
  • Kidney function tests: An examination of kidney function to assess their efficiency.
  • Blood sugar (glucose): Testing blood glucose levels to screen for diabetes or other glucose-related conditions.
  • Urinalysis: Analysis of urine to detect potential urinary tract infections or kidney issues.
  • Tests for inflammation: Non-specific tests such as sedimentation rate (sed rate) and C-reactive protein (CRP) are conducted to gauge the presence of inflammation in the body.
  • Electrolytes: Measurement of sodium, potassium, and calcium levels to provide insights into potential underlying health problems.

These blood tests serve as valuable diagnostic tools, helping your healthcare provider to identify and understand the root cause of your condition, leading to more accurate and effective treatment approaches.


Endoscopy procedures, such as an upper gastrointestinal (GI) endoscopy or colonoscopy, are valuable in searching for evidence of gastrointestinal factors contributing to weight loss.

Additionally, an echocardiogram, which utilizes ultrasound technology, plays a crucial role in diagnosing various conditions, including infections affecting the heart valves, such as infectious endocarditis. These diagnostic procedures aid healthcare providers in identifying potential underlying causes of weight loss and other health concerns, enabling them to formulate appropriate treatment strategies.

Imaging Studies

Imaging tests play a crucial role in the diagnostic process and can provide valuable insights into potential underlying causes of weight loss. Some of the helpful imaging tests include:

  • Chest X-ray: Although a plain chest X-ray is commonly used, it’s important to note that it may not always detect certain conditions like lung cancer.
  • Computerized tomography (CT) scan of the chest or abdomen: CT scans are effective in providing detailed images of the chest or abdominal region, aiding in the detection of abnormalities.
  • Magnetic resonance imaging (MRI): MRIs are useful in visualizing soft tissues and organs with high precision, helping to identify potential issues.
  • Positron emission tomography (PET) scan: PET scans are valuable in detecting evidence of cancer metastases, assisting in the evaluation of cancer spread.

By utilizing these imaging techniques, healthcare providers can gather vital information to further investigate and diagnose the potential causes of unexplained weight loss, enabling them to implement appropriate treatment strategies and provide comprehensive care.


Unintentional weight loss carries significant implications for overall health, making it crucial to investigate the underlying cause. Not only can unexplained weight loss indicate potential health issues, but it can also complicate the treatment and recovery process for other conditions, such as coronary artery disease.

Several of the underlying causes responsible for unintentional weight loss are serious medical conditions in their own right. Seeking professional healthcare guidance and undergoing necessary tests is essential to determine the most appropriate course of action and potentially improve outcomes. This proactive approach is vital because weight loss itself is associated with higher mortality rates and a diminished quality of life for individuals affected by these illnesses.

By addressing unexplained weight loss promptly and comprehensively, healthcare providers can work towards enhancing patients’ overall well-being and managing any underlying health conditions more effectively. Early diagnosis and intervention can play a pivotal role in improving the prognosis and long-term health outcomes for those experiencing unintentional weight loss.


The treatment approach for unintentional weight loss depends on identifying and addressing the underlying cause or causes, which are likely present in most cases. Some of the causes of unintentional weight loss may be less common, necessitating multiple visits and investigations to determine the root cause.

It is essential to recognize the significance of treating the weight loss itself, even if a specific cause is identified through exams, blood tests, or other diagnostic procedures. While focusing on treating the underlying condition is vital, overlooking the weight loss can have adverse effects on a person’s overall health.

To effectively address unintentional weight loss, it is crucial to have open communication with your healthcare provider. Discussing the appropriate course of action for managing weight loss based on the specific diagnosis and individual health needs is imperative.

For individuals diagnosed with cancer, it is essential to consider a palliative care consultation. Palliative care teams specialize in addressing concerns beyond cancer-related treatments, such as chemotherapy or radiation therapy. They can offer valuable support and management for issues like unintentional weight loss, ensuring comprehensive care and improving the overall quality of life for cancer patients.

By adopting a holistic approach that considers both the underlying cause of weight loss and the weight loss itself, healthcare providers can work towards better health outcomes and enhanced well-being for individuals experiencing unintentional weight loss.


Unexplained weight loss might initially appear inconsequential or even go unnoticed, leading some individuals to disregard it. However, it serves as a crucial clue that an underlying illness may be present, requiring prompt diagnosis and treatment. Consulting a healthcare provider is paramount in identifying the root cause of the weight loss and addressing both the underlying condition and the weight loss itself.

By seeking professional medical guidance, individuals can receive comprehensive evaluations, undergo appropriate tests, and work collaboratively with their healthcare provider to determine the underlying health issue responsible for the weight loss. Treating the root cause is essential for optimal health outcomes and to ensure that any potential health concerns are managed effectively.

In summary, unexplained weight loss should never be overlooked or dismissed as it often signals an underlying medical condition that necessitates attention and care. Emphasizing the significance of early detection and intervention, individuals can take proactive steps towards better health and well-being with the guidance of their healthcare provider.


1. What is the most common reason for unintentional weight loss?

The impact of age plays a significant role in determining the underlying causes of unexplained weight loss. Research findings indicate that the reasons for weight loss can vary depending on age groups.

For instance, in a study involving 2,677 individuals experiencing unexplained weight loss, with an average age of 64, cancer was identified as the most common cause.10 On the other hand, a similar study focusing on individuals aged 65 and older highlighted nonmalignant factors, such as a diminished sense of taste and appetite due to medication use, as the leading contributors to weight loss.11

Despite advances in medical knowledge, some cases of unintentional weight loss still remain unexplained. According to further research, up to a quarter of individuals experiencing unexplained weight loss do not have a clear identifiable cause.12 This highlights the complexity of the human body and the need for further investigation and research to fully understand the mechanisms behind unexplained weight loss in certain cases.

The variation in underlying causes based on age underscores the importance of considering age as a relevant factor when assessing and diagnosing unexplained weight loss. Individualized approaches are vital in determining the most appropriate course of action for addressing unintentional weight loss in different age groups, ultimately leading to better health outcomes and improved quality of life for affected individuals.

2. When should you worry if you start losing weight without trying?

While any amount of weight loss can be a cause for concern, the medical definition of unintentional weight loss is specifically characterized by a loss of 10 pounds or 5% of the total body weight within a period of six to 12 months. This definition is especially relevant for individuals aged 65 and older, as they are more susceptible to experiencing unintentional weight loss compared to other age groups.13

Recognizing and monitoring weight loss within these parameters is crucial for early detection and intervention, as unintentional weight loss can be a sign of underlying health issues that require attention and medical evaluation. It is essential for individuals and healthcare providers to remain vigilant and address any significant or unexplained changes in weight, especially in older adults, to ensure that potential health concerns are promptly identified and managed effectively.

3. What types of cancer most often cause weight loss?

Cachexia, a type of weight loss commonly observed among cancer patients, is characterized by the loss of both muscle mass and fat. This condition is most frequently associated with certain types of cancer, including cancer of the pancreas, stomach (gastric cancer), lung, esophagus, colon, and head or neck.

Cachexia is a serious complication of cancer and can have a significant impact on a patient’s overall health and quality of life. It often leads to weakness, fatigue, and a decreased ability to perform daily activities. Managing cachexia is essential for optimizing the well-being of cancer patients and supporting their treatment and recovery journey.

Healthcare providers play a crucial role in identifying cachexia early on and implementing appropriate interventions to address this weight loss complication, aiming to enhance patients’ nutritional status and overall health during their battle against cancer.

References & Disclaimer:

TGH Urgent Care powered by Fast Track is committed to providing accurate, reliable, and trustworthy information in their articles. To ensure the credibility of their content, they rely on high-quality sources, including peer-reviewed studies, when presenting facts and information.

Some of the reputable sources used to support the facts within their articles include:

  1. Gaddey HL, Holder KK. Unintentional Weight Loss in Older Adults. Am Fam Physician. 2021 Jul 1;104(1):34-40. PMID: 34264616.
  2. BMJ Best Practice. Evaluation of unintentional weight loss. British Medical Association.
  3. Perera LAM, Chopra A, Shaw AL. Approach to patients with unintentional weight loss. Medical Clinics of North America. 2021;105(1):175-186. doi: 10.1016/j.mcna.2020.08.019
  4. 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-analysis. British Journal of General Practice. 2018;68(670):e311-e322. doi:10.3399/bjgp18X695801
  5. American Thyroid Association. Graves’ disease.
  6. Siddiqui JA, Pothuraju R, Jain M, Batra SK, Nasser MW. Advances in cancer cachexia: Intersection between affected organs, mediators, and pharmacological interventions. Biochimica et Biophysica Acta (BBA) – Reviews on Cancer. 2020;1873(2):188359. doi: 10.1016/j.bbcan.2020.188359
  7. American Psychiatric Association. What Is Depression?
  8. National Institute of Diabetes and Digestive and Kidney Diseases. Adrenal insufficiency & Addison’s disease.
  9. 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
  10. Bosch X, Monclús E, Escoda O, et al. Unintentional weight loss: Clinical characteristics and outcomes in a prospective cohort of 2677 patients. PLoS One. 2017;12(4):e0175125. doi:10.1371/journal.pone.0175125
  11. Gaddey HL, Holder KK. Unintentional weight loss in older adults. Am Fam Physician. 2021;104(1):34-40.
  12. Perera LAM, Chopra A, Shaw AL. Approach to patients with unintentional weight loss. Med Clin North Am. 2021;105(1):175-186. doi:10.1016/j.mcna.2020.08.019
  13. Cleveland Clinic. Unexplained Weight Loss.

Incorporating evidence-based information from these reputable sources ensures the reliability and accuracy of the information presented by TGH Urgent Care powered by Fast Track.

Disclaimer: The information provided in this article is for informational purposes only and is not intended as medical advice. TGH Urgent Care powered by Fast Track is not providing medical diagnosis, treatment, or recommendations. The content presented here is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it based on the content of this article. If you have a medical emergency, call your local emergency services immediately. Reliance on any information provided in this article is solely at your own risk. TGH Urgent Care powered by Fast Track is not liable for any errors or omissions in the content or for any actions taken based on the information provided herein.


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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