Weight loss is usually the desired outcome of a new diet or a fitness regime. However, people may experience a noticeable drop in weight without changing their eating habits or exercising more often. This unexplained weight loss can be associated with an underlying medical condition that requires medical attention.

This article outlines probable causes of unintentional weight loss and explains how to regain health and strength through prevention, diagnosis, and treatment.

What Is Unexplained Weight Loss?

Unexplained weight loss is a significant drop in body weight without changing your diet or exercise routine. Depending on the underlying cause, sudden unwanted weight loss may be accompanied by the following symptoms:

• Loss of muscle mass and muscle weakness
• Changes in skin and hair
• Fatigue
• Loss of appetite
• Gastrointestinal problems: diarrhea, constipation, abdominal pain, bloating, nausea and vomiting.
• Increased thirst and urination
• Shortness of breath and palpitations
• Psychological symptoms: depression, anxiety, stress

People who start shedding pounds without intentional dieting or increased physical activity are advised to seek medical help, as this type of weight loss may indicate an underlying health problem, such as a hormonal imbalance, diabetes, or cancer.

How Much Unexplained Weight Loss Is Concerning?

Losing more than 5% of your weight within six to twelve months without an apparent reason is alarming, especially if you are 65 or older. It could indicate an underlining health problem, especially if accompanied by other symptoms (e.g., abdominal discomfort, reduced appetite, or fatigue).

For example, if you weigh 150 pounds (68 kilograms), dropping seven and a half pounds (3.4 kilograms) within six to twelve months would be considered concerning. Consult a healthcare provider to determine the cause and reduce health risks.

What Causes Unexplained Weight Loss?

A sudden drop in body weight can stem from medical and non-medical causes or from a combination of factors. While not all weight loss is serious, it can signal an underlying health condition that has to be addressed and treated promptly.

Closely observe any additional symptoms accompanying the condition to identify the root cause. Certain health issues may contribute to unintentional weight loss by decreasing your appetite, preventing calorie absorption, or accelerating calorie burning.

Stress

Chronic stress and stressful events (e.g., losing a loved one, a divorce, or losing a job) can disrupt metabolism, reduce appetite, and cause a significant caloric deficit. Elevated cortisol levels may lead to a stress-induced hormonal imbalance that affects vital bodily functions and impacts how you store fat, nutrients, and calories.

Malnutrition

Inadequate diet deprives your body of essential nutrients, such as fatty acids, vitamins, and minerals. A diet lacking protein and healthy fats can significantly decrease body weight, cause muscle waste, and dysregulate metabolism.

Note: Discover 10 powerful vitamins for an immune system boost.

Lack of Sleep

Sleep deprivation can disrupt hunger-regulating hormones (e.g., ghrelin and leptin), increase stress levels, and reduce overall appetite. Lack of sleep or hormonal insomnia may also impair the body's ability to properly metabolize food, leading to nutritional deficiency and reduced calorie absorption.

Muscle Atrophy

Physically inactive people, especially those who are bedridden due to an illness or an injury, can lose weight by wasting muscle tissue. Lack of movement and exercise can gradually lead to muscle atrophy (i.e., loss of muscle mass), reducing strength, causing weakness, and worsening overall health.

Gastrointestinal Problems

Digestive issues can cause a sudden drop in weight by reducing appetite, increasing metabolism, or impairing the intestine’s ability to absorb nutrients. Some health conditions cause caloric deficits by provoking diarrhea and vomiting, while others impair digestion by altering the gut microbiome.

The following gastrointestinal problems may lead to unintentional weight loss:

• Gastroenteritis
• Inflammatory bowel disease (IBD)
• Irritable bowel syndrome (IBS)
• Malabsorption syndrome
• Ulcerative colitis
• Peptic ulcer disease
• Celiac disease
• Crohn’s disease

Note: Learn about the connection between gut health and hormones.

Diabetes

Unexplained weight loss may affect patients with type 2 diabetes but is more common in people diagnosed with type 1 diabetes. Lack of insulin or ineffective use of insulin means the body can’t transport the glucose to cells for energy and starts burning fat and muscle to obtain it. High blood sugar also triggers excessive urination, leading to dehydration. Dehydration itself can cause some weight loss due to the loss of water weight. Additionally, the body's effort to excrete glucose also means it is losing calories through urine, contributing further to unintentional weight loss.

Mental Health Issues

Undesired weight loss may result from a psychological problem or a mental health disorder, including the following:

• Mood swings
• Anxiety
• Depression
• Eating disorders
• Obsessive compulsive disorder (OCD)
• Anorexia nervosa
• Bulimia nervosa

Unresolved trauma, mental health issues, and compromised emotional wellbeing can reduce appetite, disrupt the hunger-regulating hormones, and trigger a predisposition to disturbed eating habits that gradually slim you down.

Malfunctioning Thyroid

An overactive thyroid (i.e., hyperthyroidism) accelerates metabolism, leading to faster fat-burning and rapid weight loss. Patients diagnosed with this condition may also experience hand tremors, increased or irregular heartbeat, heat sensitivity, and irritability.

Note: Read more about the connection between thyroid and metabolism. 

Adrenal Insufficiency  

Adrenal insufficiency, also known as Addison’s disease, is a rare condition that affects the adrenal gland system, causing changes in skin tone, dizziness, fatigue, and unexpected weight loss. If the adrenal glands produce insufficient amounts of adrenaline, cortisol, and aldosterone, you may experience loss of appetite and dysfunctional metabolism, leading to unwanted weight reduction.

Chronic or Acute Infections

Both chronic and acute infections may reduce your body mass index (BMI) and increase inflammation. They cause symptoms such as diarrhea, vomiting, difficulty swallowing, and malabsorption, which can lead to weight loss.

The most common infections that lead to unintentional weight loss are the following:

• HIV/AIDS
• Tuberculosis
• Chronic hepatitis
• Chronic salmonella
• Fungal infections (e.g., candidiasis)
• Parasitic infections (e.g., tapeworm, hookworm, and giardiasis)

Dental Health Issues

Dental health problems, such as cavities, gum disease, toothaches, and temporomandibular joint (TMJ) disorders, can lead to unwanted weight loss by making chewing and swallowing difficult. This is especially problematic if dental issues last for an extended period.

Neurological Disorders

Neurological disorders, such as dementia, multiple sclerosis, Parkinson’s, or Alzheimer’s disease, increase the risk of unwanted weight loss by impairing swallowing and affecting appetite regulation and motor function. Strokes can cause problems with coordination, tremors, and muscle weakness, contributing to a loss of appetite and difficulty preparing or consuming food.

Cancer

Cancer causes muscle wasting, increases inflammation, and impacts how much energy your body burns at rest. It also disrupts appetite-regulating hormones, leading to unexpected weight loss, fatigue, fever, increased metabolism, and reduced appetite.

 The most significant cancer-related weight loss was observed in patients with pancreatic cancer and lymphoma, followed by those with kidney, bladder, and ureteral cancers. Other forms of cancer that have been linked to unexplained weight loss are prostate, colorectal, lung, throat, ovarian, skin, and bile duct cancer.

Medications and Therapies

Certain prescription, off-the-counter drugs and therapies can alter taste and smell, suppress appetite, and provoke nausea, vomiting, dry mouth, and difficulty swallowing. All these factors increase the likelihood of unwanted weight loss over time.

The following medications and treatments can provoke this condition:

• Antidepressants
• Antibiotics (e.g., penicillin)
• High blood pressure drugs (e.g., hydralazine)
• Stimulants for treating ADHD (e.g., methylphenidate)
• Heart medication (e.g., digoxin)
• Antiepileptic drugs (e.g., topiramate, felbamate, and zonisamide)
• Chemotherapy

Substance Use Disorders

Drug addiction, prescription drug abuse, and alcohol use disorder can lead to unwanted weight fluctuations by suppressing appetite, increasing metabolism, and provoking or worsening gastrointestinal issues. Substance use disorders impact overall health and lead to poor eating habits and nutritional deficiencies that make weight management even more challenging.

Blood Imbalances

Blood imbalances impair the body’s ability to carry oxygen and nutrients to tissues, leading to weakness, reduced appetite, and fatigue. Electrolyte imbalances also cause nausea, vomiting, and diarrhea.

The following blood disorders may lead to unintentional weight loss:

• Hypercalcemia - High blood calcium levels caused by medical supplements or overactive parathyroid glands can cause abdominal and muscle pain, digestive issues, and kidney disorders.
• Hyponatremia – Drinking alcohol, dehydration, and diarrhea can lower blood sodium levels, causing nausea, vomiting, loss of energy, and muscle cramps.
• Hyperglycemia - High blood sugar levels associated with insulin resistance and diabetes can cause dry mouth, blurred vision, and tiredness.
• Anemia – Marked by low red blood cell count and usually caused by iron or vitamin B12 deficiency, may lead to tiredness, weakness, and loss of appetite.

Note: Discover the link between anemia and weight loss and how this blood disorder affects weight.

Other Health Conditions

Losing weight may result from an underlying health issue that requires medical attention. The most common conditions associated with unwanted weight loss are the following:

• Rheumatoid arthritis (RA)
• Endocarditis
• Pancreatitis
• Congestive heart failure (CHF)
• Chronic obstructive pulmonary disease (COPD)
• Amyloidosis
• Fatty liver disease (FLD)
• Chronic kidney disease (CKD)

How Is Unexplained Weight Loss Diagnosed?

A healthcare provider can determine the root cause of unwanted weight loss through a comprehensive medical evaluation consisting of the following diagnostic steps:

• Discussing the patient's medical record, symptoms, lifestyle changes, and medications.
• Assessing the patient’s overall health through a physical examination.
• Reviewing recent cancer screenings and related medical documentation (e.g., mammogram and PSA tests).
• Blood testing to identify conditions like thyroid disorders, nutrient deficiencies, diabetes, celiac disease, and infections.
• Urine testing to identify infections, kidney function, diabetes, metabolic disorders, and electrolyte imbalances.
• Food allergy testing to identify celiac disease, food intolerance, and food allergies.
• Mental health screening and psychological assessment.
• Dental examination to determine if any oral infections or dental problems make chewing, swallowing, and eating difficult.
• Barium swallow test to help discover any diseases, tumors, and cancers in the GI tract.
• Performing imaging scans such as X-rays, CT scans, MRI, and ultrasound.
• Referring to a specialist for additional testing in case of inconclusive diagnosis.

However, scientists have found that a quarter of people who lose weight without conscious effort do not get a definitive diagnosis. In that case, doctors usually recommend waiting and monitoring for new symptoms.

Can Unexplained Weight Loss Be Prevented?

The following strategies can effectively prevent unexplained weight decrease:

• Maintain a balanced diet rich in fatty acids, protein, and fiber.
• Schedule regular medical check-ups to monitor and manage health conditions (e.g., diabetes and hyperthyroidism).
• Schedule annual cancer screening tests, especially if you have a family history of malignant illnesses.
• Take prescribed medications and discuss potential side effects with your doctor.
• Consult your healthcare provider about new supplements, medications, and dietary changes if you are prone to weight oscillations.
• Monitor body weight and keep track of any weight changes.
• Seek professional medical advice if you notice any unusual symptoms, such as appetite loss or belly ache.
• Engage in regular physical exercise to stay fit, strong, and healthy.
• Pick a stress-relieving activity to manage stress and prevent unwanted weight loss.
• Get vaccinated to prevent infections and severe diseases that may affect your weight.
• Avoid recreational drugs and drink alcohol in moderation.
• Visit the dentist every six to twelve months and practice regular dental hygiene to keep your teeth and gums healthy.

How to Treat Unexplained Weight Loss?

There are effective methods to treat and manage unwanted weight loss, but it is important not to try any treatments on your own. Always consult a healthcare professional or specialist to identify the underlying cause and receive appropriate care.

Use Supplements

Dietary supplements can support the gut, improve appetite, prevent muscle wasting, and restore nutritional deficiencies. They also support muscle mass retention, enhance metabolic function, and increase overall energy.

Incorporate the following supplemental products to promote healthy weight gain:

• Appetite stimulants - Natural hunger-inducing supplements like fenugreek, zinc,  thiamine, and fish oil.
• Protein powders – Whey, casein, and plant-based protein powders help build muscle and manage healthy weight.
• Meal replacement shakes – These nutrient-dense, ready-to-drink beverages can be a valuable addition to a balanced diet.
• Gut-supporting supplements – Improve gastrointestinal function by promoting a healthy gut microbiome, relieving symptoms like bloating, constipation, and diarrhea.
• Digestive aids – Contain pancreatic enzymes that help break down dairy, fats, proteins, and carbs to assist digestion and ensure nutrient absorption.
• Omega-3 fatty acids – Omega-3s help reduce inflammation of the gut, reduce gut permeability and alleviate symptoms like bloating and cramps.
• Probiotics – Probiotic supplements aid digestion, support healthy gut flora, and may help ease symptoms of irritable bowel syndrome (IBS).
• Mineral supplements – Zinc and vitamin B1 (thiamine) help increase appetite, iron helps support gut bacteria, and B vitamins promote healthy fat gain.
• Vitamin supplements – Vitamin-based supplements aid weight management by boosting the immune system, balancing hormones, and correcting nutrient deficiencies.
• Collagen peptides – These strengthen muscles, bones, and joints.

Medications and Therapies

Unintended weight loss can be reversed with prescription drugs and medical treatments that address the underlying health condition. A licensed dietitian can provide nutritional counseling and tailor a customized eating plan for regaining strength, bone mass, muscle mass, and fat.

Drugs used to treat unintentional weight loss include the following:

• Cyproheptadine – An antihistamine that also works as an appetite stimulant.
• Dronabinol (Marinol, Syndros) – This synthetic form of tetrahydrocannabinol (THC) increases appetite in people with AIDS and helps reduce severe nausea and vomiting after chemotherapy.
• Megestrol (Megace ES) – An artificial drug chemically similar to progesterone treats loss of appetite and wasting syndrome in people diagnosed with AIDS.
• Oxandrolone (Oxandrin) – This anabolic steroid, chemically similar to testosterone, promotes muscle tissue growth, reduces bone pain, and helps regain weight after injury, surgery, and chronic infection.
• Somatropin (Serostim) – This human growth hormone is used in adults to treat short bowel syndrome and minimize AIDS-triggered weight loss.

Change Your Diet

The following guidelines can help you regain lost weight in a healthy, sustainable manner:

• Increase caloric intake to match the desired weight goal.
• Eat protein-rich foods to build and maintain muscle mass.
• Adopt a nutrient-dense diet rich in healthy fats, proteins, and complex carbohydrates.
• Choose anti-inflammatory dieting plans that reduce inflammation and prevent chronic illnesses, flare-ups, and infections.
• Consult a professional nutritionist to obtain a calorie-appropriate diet plan and ensure its safety and effectiveness.

Manage Stress

Excessive stress can impair both physical and mental health, increasing the risk of chronic illnesses that may result in unwanted weight loss. Learning to lower cortisol is the first step in restoring overall health and regaining lost pounds.

Vitamins for stress support the body’s response to chronic stress, improve sleep, increase energy, and strengthen the immune system. The most effective stress-suppressing vitamins are:

• B complex (e.g., vitamin B12 injections)
• Vitamin D
• Vitamin C

Stress-relieving supplements contain potent natural ingredients that promote calmness and relaxation and reduce nervousness, anxiety, and depression. They help optimize cortisol activity to enhance stress-resilience and improve overall health.

What Are the Consequences of Not Treating Unexplained Weight Loss?

Not treating this condition may lead to moderate to severe health consequences, including the following:

• Fatigue
• Gastrointestinal issues
• Nutritional deficiencies
• Weakened immunity
• Muscle atrophy or waste
• Organ dysfunction
• Mental health issues
• Increased mortality risk
• Chronic infections

Seek professional medical care if you notice suspicious or unexplained weight fluctuations, including both weight gain and weight loss.

Conclusion

Unintentional weight loss can be concerning, especially if accompanied by symptoms such as gut issues, pain, or fatigue. Identifying the root cause and addressing it with appropriate treatment and medication is the first step in regaining lost weight and restoring both physical and mental health.

If you suspect your health is compromised due to unusual weight fluctuations, consult our friendly healthcare team at Vibrant Vitality Clinic.