Causes of Unexplained Weight Loss and Medical Advice

Understanding Unexplained Weight Loss  

Unexplained weight loss, also unintentional weight loss or unexpected weight loss, means losing weight without trying. Specifically, it refers to a weight loss of 10 pounds or more or 5% of your initial or baseline body weight in 6 months or less. This symptom can be a sign of serious illness, especially in an older adult, and should be evaluated by a healthcare professional. 

Prevalence and Demographics  

Studies show that unintentional weight loss occurs in up to 8% of adults and 27% of frail older adults (people aged 65 years and older with a low baseline body weight).

Impact on Health  

Unintentional weight loss is linked to a 10-40% higher risk of death within 1 to 2.5 years, especially in frail, elderly individuals and older adults with recent hospital admissions. Unexplained weight loss is also linked to a higher risk of in-hospital medical complications, higher rates of admission to assisted living facilities and nursing homes, a decline in the ability to do activities of daily living and live independently, and an overall poorer quality of life.

Possible Causes of Unexplained Weight Loss  

Medical Conditions That Can Contribute to Weight Loss  

• Endocrine or hormonal disorders such as Addison’s disease in which low aldosterone and cortisol levels can lead to increased metabolism and unintentional weight loss. Additional symptoms of Addison’s disease include nausea, vomiting, diarrhea, and loss of appetite.

• Hyperthyroidism (too much thyroid hormone or overactive thyroid) can increase metabolism and cause you to lose weight.

• Viral infections: Rapid weight loss and muscle loss is common in patients with late-stage acquired immunodeficiency syndrome (AIDS).

• Malignancy: Unintentional weight loss can be a sign of cancer.

• Gastrointestinal conditions: Digestive system conditions such as celiac disease can cause you to lose weight due to symptoms such as vomiting and diarrhea. They can also lead to nutritional deficiencies.

• Inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis, are autoimmune disorders in which the immune system attacks healthy cells in the gastrointestinal tract. Other symptoms include loss of appetite, nausea, and chronic diarrhea, in addition to losing weight. 

• Chronic pancreatitis (long-term inflammation of the pancreas) can decrease appetite and cause unintentional weight loss.

• Stomach ulcers: Symptoms of peptic ulcer disease include nausea, vomiting, and loss of appetite, which can affect weight.

• Certain parasitic infections can cause diarrhea and vomiting, which can result in weight loss.

• Neurodegenerative conditions such as advanced dementia are linked to unintentional weight loss because of memory problems, trouble swallowing, loss of appetite, and dental issues.

• Parkinson’s disease: People with Parkinson’s disease may experience loss of body weight due to symptoms such as anosmia (loss of smell), dysphagia (problems with swallowing), nausea, loss of appetite, depression, and problems feeding due to poor muscle control. 

• Dental problems, such as trouble chewing, gum disease, tooth decay, toothaches, and temporomandibular joint (TMJ), can affect appetite and the ability to eat, which can cause a person to lose weight.

• Diabetes: People with undiagnosed or undertreated type 2 diabetes (high blood sugar) may experience unexpected weight loss because their body burns fat instead of glucose for energy.

• Congestive heart failure: Late-stage heart failure, a condition that affects the heart’s ability to pump blood, can be associated with a decrease in body weight. 

Losing Weight Due To Psychological and Emotional Influences  

• Eating disorders: An undiagnosed eating disorder such as anorexia nervosa and bulimia nervosa can present with unexplained weight loss as an early symptom. 

• Other mental illnesses: Weight loss can also occur in mental health conditions such as depression and anxiety due to a lack of interest in eating. 

• Behavioral conditions: A behavioral condition called obsession with exercise, also known as exercise addiction or compulsive exercise, is associated with exercising for long hours or doing a strenuous exercise routine, which can burn large numbers of calories and result in weight loss. 

Medications

• Prescription drugs: Weight loss is a known side effect of certain prescription medications, such as some antibiotics, stimulants used to treat ADHD, antiepileptic drugs, and chemotherapy drugs.

• Other medication side effects: Certain medications can cause side effects such as a decreased appetite, an unpleasant taste in the mouth, dry mouth, altered sense of smell or taste, problems with swallowing, nausea, or vomiting. These side effects can result in a person losing weight due to decreased intake of calories. 

Lifestyle and Environmental Factors That Can Make You Lose Weight

• Mental stress: A stressful event, such as a divorce, job loss, or death of a loved one, can lead to loss of appetite and weight loss.

• Tobacco use: Smoking can lead to weight loss due to reduced appetite and decreased metabolic rate, metabolic efficiency, and caloric absorption.

• Substance abuse: Alcohol and drug abuse (substance use disorders) can affect appetite, cause nausea and vomiting, and result in liver damage, which can lead to weight loss.

Diagnosis of Unexplained Weight Loss  

When to Seek Professional Help  

Seek professional help from a healthcare provider if you notice unexpected weight loss of more than 10 pounds or 5% of your baseline weight within 6 months. This can be a sign of serious illness and should be evaluated. The sooner you seek medical attention, the more likely the underlying health condition can be treated or cured.

Initial Medical Evaluations and Tests  

Your doctor will listen to your symptoms, obtain a thorough medical history, review your list of current medications, assess your risk factors for certain medical conditions, and perform a physical examination. They may also order a range of tests to find out the cause of unintentional weight loss, such as:

• Blood tests to identify an underlying condition such as an infection, diabetes, celiac disease, nutrient deficiencies, thyroid disorders, or adrenal gland conditions.

• Urine tests such as urinalysis to assess kidney and bladder function and certain other infections and medical conditions.

• Screening for cancer with blood tests to measure tumor markers.

• Imaging studies such as endoscopy, colonoscopy, X-rays, ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) to obtain images of organs inside the body.

Specialist Consultations  

Your primary care provider may refer you to specialists based on the results of your initial evaluation. For example, if the initial assessment shows malnutrition or deficiencies of certain nutrients, they may refer you to a gastroenterologist to look for digestive system conditions that can affect nutrient absorption from the gut and cause unintended weight loss. If you have dental issues, they may refer you to a dentist for appropriate treatment. 

Treatment and Management of Unexplained Weight Loss  

Medical Treatments and Interventions  

As mentioned, certain health conditions can cause unexpected weight loss. Treatment, therefore, depends on the underlying cause. For example, if unintentional weight loss has occurred after starting a new medication, your doctor may change the dose of the medicine or switch you to a different drug. If a problem is found with the adrenal glands (Addison’s disease), hormone replacement therapy can help people gain weight. 

Dietary and Lifestyle Modifications  

If your unexplained weight loss is due to diet or lifestyle factors such as an overly strenuous exercise routine, you may benefit from a nutritional consultation with a licensed dietitian or a talk therapy with a mental health professional.

Psychological Support and Counseling  

If a stressful event or mental health condition is the underlying cause of your losing weight, your healthcare provider may refer you to a mental health professional for psychological counseling and therapy. 

Unexplained Weight Loss and Associated Risks  

Risk of Serious Illnesses  

As mentioned, unintentional weight loss (losing weight without trying) can be a sign of serious illnesses. It should be evaluated promptly so that the cause can be found and treated.

Gender Differences in Causes and Risks  

People of all ages and genders can develop unintentional weight loss. However, certain health conditions are more common in men, such as heart disease and diabetes, and others in women, such as mental health problems and digestive issues. Regardless of gender, you should seek timely care for unexpected weight loss.

Long-Term Health Implications  

Seeking timely treatment for unintentional weight loss is important because many medical conditions have poorer outcomes if they are discovered and treated in the later stages. Early diagnosis and treatment can prevent serious health complications and increase your chances of managing the condition or even being cured.

Frequently Asked Questions  

When Should I Worry About Unexplained Weight Loss?

You should worry about unexplained weight loss if you lose more than 10 pounds or more than 5% of your baseline weight within 6 months without trying.

What Diseases Cause Sudden Weight Loss?

Health conditions such as diabetes and Addison’s disease can progress rapidly and cause sudden weight loss. Other conditions, such as cancer, tend to progress more slowly and cause less rapid weight loss.

Why Have I Lost Weight Without Trying?

You might have lost weight without trying due to an underlying health condition. Make an appointment to see your doctor as soon as possible. This is a serious symptom and should be medically evaluated. 

What Type of Cancer Causes Weight Loss?

All types of cancer can cause unintentional weight loss, but it is more common in some types of cancers, including upper gastrointestinal cancers (esophageal cancer, gastric cancer, small bowel cancer, liver cancer, and pancreatic cancer), lower GI cancers (colorectal cancer), lung cancer, and blood cancers like non-Hodgkin lymphoma.