Weight fluctuations are a normal part of life, influenced by factors like hydration, hormones, and daily habits. However, significant and unexplained weight loss, especially when sick, can be a cause for concern. This article explores the causes of rapid weight loss during illness, particularly in the context of COVID-19, outlines when to seek medical attention, and provides guidance on how to regain weight safely and effectively.
When is Weight Loss Concerning?
It’s normal for weight to fluctuate daily. Weight loss becomes a concern when it’s 10 pounds or at least 5% of your original weight during a six-to-12-month period. Older adults are at higher risk for unexplained weight loss, especially if they live in a community living setting. Studies show that as many as 20% of older adults experience unexplained weight loss. For nursing home residents, that number increases to 60%, likely because the prevalence of issues causing unintentional weight loss (including cancer, gastrointestinal conditions and psychological issues) may be greater in this population.
Common Causes of Unexplained Weight Loss
Unexplained weight loss is a red flag. Weight loss cannot always be explained, especially in older adults. But, in nearly 75% of cases, an identifiable underlying issue causes the weight loss. Here are some of the most common causes of unexpected weight loss:
- Cancer: Cancer is the most common cause of unintentional weight loss - more than 35% of people who see their doctor for weight loss have undiagnosed cancer. Adults with unexplained weight loss are at least 12 times more likely to have cancer than people who aren’t experiencing weight loss. Weight loss is often the first symptom of cancer - approximately 40% of cancer diagnoses begin this way. Researchers report that people with early-stage colorectal, pancreatic and lung cancer have reported weight loss.
- Digestive Diseases and Conditions: Gastrointestinal (GI) issues account for 10% to 20% of unexpected weight loss cases. Digestive diseases can cause inflammation and malabsorption, which may affect your metabolism and hinder the body’s ability to take in calories and macronutrients. GI conditions that commonly lead to sudden weight loss include celiac disease, chronic diarrhea, inflammatory bowel diseases, overuse of laxatives, often suggesting an eating disorder
- Mental Health Issues: Mental health disorders are responsible for unintentional weight loss approximately 10% to 23% of the time. Your appetite may be affected by anxiety, depression, eating disorders, obsessive-compulsive disorder (OCD), stress. For some people, weight loss can also be the result of side effects associated with medications used to treat mental health disorders. Some medicines can cause nausea, reduce appetite or tamper with your sense of smell and taste.
- Other Possible Causes: While cancer and GI issues and mental health cause most unintentional weight loss, there are many other reasons you might suddenly lose weight, including dementia, due to changes in mealtime habits, endocrine issues, including thyroid disorders and diabetes, medication side effects, which can cause dry mouth, vomiting, nausea or altered senses that interfere with eating oral disorders, including gum disease, dysphagia (trouble swallowing) or any condition that makes it uncomfortable to eat social factors, such as alcoholism, financial limitations or difficulty getting food.
The Link Between COVID-19 and Weight Loss
While some people experienced weight gain during the initial periods of lockdown, which reduced physical activity, other patients infected with COVID-19 dealt with unintended and significant weight loss. Weight loss is a complex issue associated with COVID-19, with multiple factors contributing to its occurrence.
- Loss of Taste and Smell: One of the most common symptoms of COVID-19 is a loss of taste and smell. This can significantly impact an individual's desire to eat, ultimately leading to a reduced caloric intake.
- Gastrointestinal Symptoms: COVID-19 can cause stomach aches and other GI issues such as nausea, vomiting, and diarrhea. These symptoms can lead to dehydration and further weight loss due to fluid and nutrient loss.
- Metabolic Changes: The viral infection itself triggers an immune response, leading to a higher metabolic rate. This increased metabolism can lead to a higher demand for energy, resulting in weight loss if the individual cannot consume sufficient calories.
- Being Constipated: Constipation can impact one's appetite due to factors such as distension and discomfort in the abdomen, slowed digestive transit leading to prolonged feelings of fullness, altered gut hormones, nutrient absorption issues, and potential disruptions to the gut microbiota, all of which can contribute to appetite fluctuations
- Stress and Anxiety: The stress and anxiety associated with COVID-19 can affect an individual's eating habits and lead to unintentional weight loss.
Recognizing the Signs of COVID-19 Weight Loss
One of the primary reasons why weight loss might be overlooked during COVID-19 infection is its gradual onset. As a result, it’s essential to pay attention to certain signs of COVID-19 weight loss.
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- Loss of Appetite: A diminished appetite is one of the most common indicators of weight loss during COVID-19. Infected individuals may experience a reduced desire to eat or find themselves not consuming their usual portion sizes.
- Loose-Fitting Clothes and Accessories: As weight diminishes, clothes and rings may start to fit more loosely than before. People might notice their belts tightening an extra notch or their favorite rings sliding off their fingers with greater ease, indicating a potential reduction in body mass.
- Poorly Fitting Dentures: Weight loss can lead to changes in facial structure, including the jawline, which can impact the fit of dentures.
- Fatigue and Lack of Energy: Weight loss, particularly when accompanied by other symptoms, can lead to a general feeling of tiredness and decreased energy levels. This exhaustion may further impact an individual's daily activities and overall quality of life.
- Difficulty Concentrating: As the body changes due to weight loss, individuals might experience difficulty concentrating or mental fogginess. This cognitive impact can affect work performance, academic achievements, and overall mental well-being.
Typical Amount of Weight Loss During COVID-19
The amount of weight loss experienced by COVID-19 patients can vary widely depending on various factors, including the severity of the infection and the individual's overall health. In milder cases, you may not experience any weight loss, or it may be minimal. However, in more severe cases or prolonged illnesses, weight loss can be substantial. Research indicates that even moderate cases of COVID-19 can lead to a loss of greater than 5% of baseline body weight.
Complications Related to COVID-19 Weight Loss
While some weight loss may be expected during a COVID-19 infection or any type of prolonged illness, significant COVID weight loss can lead to a variety of complications, including:
- Malnutrition
- Muscle loss
- Weakness or fatigue
- Anemia
- Elevated C-reactive protein levels, indicating inflammation
- Prolonged disease duration
- Impaired kidney function
Regaining Weight After COVID-19: A Healthy Approach
For individuals who have experienced weight loss due to COVID-19, regaining weight healthily and sustainably is vital for a full recovery. Here are some tips to facilitate weight gain:
- Balanced Diet: Focus on consuming a balanced diet that includes a variety of nutrients. Incorporate lean proteins, whole grains, fruits, vegetables, and healthy fats to promote weight gain.
- Frequent, Smaller Meals: Eating smaller, more frequent meals can be easier on the digestive system and help increase caloric intake.
- Stay Hydrated: Ensure adequate hydration to avoid further complications and support nutrient absorption.
- Exercise Gradually: Gradually incorporate light exercises to rebuild strength and muscle mass as recovery progresses.
- Seek Professional Guidance: Consult a healthcare professional or a registered dietitian to develop a personalized plan for healthy weight gain. If you continue to experience a decrease in appetite impacting your weight, your doctor may prescribe you some appetite stimulants.
When to Seek Medical Attention
If you’ve lost a concerning amount of weight in recent months, the first step should be consulting with your primary care physician (PCP). Identifying an underlying cause of unexplained weight loss can be challenging and may require a lot of diagnostic testing and time. To pinpoint the cause of your weight loss, your physician may recommend a diagnostic process that includes:
- Physical exam and medical history to identify additional symptoms or risks
- Blood tests to measure important factors such as metabolism and thyroid function
- Urine analysis to identify any infections and check kidney and bladder function
- Mental health screening to pinpoint emotional and mental issues that may interfere with your appetite or eating
- Imaging, such as MRI or a CT scan, to rule out tumors or other diseases
Losing weight without trying may be a sign of a health problem.Persistent fever can mean you have an infection, including COVID-19. If you have a fever and other symptoms, such as cough and fatigue, contact your health care provider right away for medical advice. Your health care provider will likely recommend that you get tested for COVID-19. If you have emergency COVID-19 symptoms, such as trouble breathing, seek care immediately. If you need to go to a hospital, call ahead. A fever can also be a symptom of many other infectious diseases, from a urinary tract infection to tuberculosis. Call your health care provider if your temperature is 103 F (39.4 C) or higher. You might have this feeling, known as early satiety, along with nausea, vomiting, bloating or weight loss.
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Tests for Unexplained Weight Loss
A healthcare provider may order specific medical tests based on your symptoms, family history and other factors. For example, if you have symptoms of a peptic ulcer, your provider may recommend an upper endoscopy. Other tests may include:
- Blood tests: Your blood can show signs of certain health conditions like diabetes, celiac disease and infections. It can also give your provider information about how your metabolism, thyroid and adrenal glands are working.
- Cancer screening tests: If your provider wants to rule out cancer, you may need screening or imaging tests. For example, a colonoscopy can detect colorectal cancer.
- Imaging tests: Tests like an MRI (magnetic resonance imaging) or CT scan (computed tomography scan) can provide detailed images of your organs, like your brain, heart, lungs and abdominal organs. You may need one of these tests if your provider wants to rule out tumors or diseases that may be visible on these scans.
- Urine test: A urinalysis can provide information about your kidneys and bladder, including certain health conditions and infections.
Treatment and Prevention
Your treatment for unexplained weight loss depends on what’s causing it. For example, if you have a toothache, you may need to see a dentist. If the cause is a peptic ulcer, your provider may treat it with antibiotics. People with celiac disease must avoid all gluten.
Many of the conditions that lead to unexplained weight loss can’t be prevented. But there are some steps you can take to help prevent some of them, including:
- See your primary care provider for an annual physical exam.
- Get poked and checked! Be sure that you receive all recommended vaccines and cancer screenings.
- Take prescription medications as instructed. Reach out to your healthcare provider if you experience any side effects, including changes in appetite or weight after starting a new medication.
- Take good care of your teeth and gums.
Unexplained Weight Loss: Important Considerations
Not all weight loss is serious. Weight loss can occur after a life changing or stressful event. However, significant unexplained or unintentional weight loss may be an early sign of an underlying medical condition.
Diagnosing the cause of unexplained weight loss usually begins with a thorough evaluation, during which the doctor will ask about other symptoms and medical history. The specific symptoms you experience may help a doctor recommend specific tests. If the cause is not apparent, they may recommend more general testing and exams to rule out specific health conditions.
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Doctors don’t always recognize unexplained weight loss. In a 2023 study, researchers found that doctors recognized this as a symptom in only 21% of cases. The specific treatment for unexplained weight loss depends on the underlying cause. Research suggests that a quarter of people with unexplained weight loss may not get a diagnosis even after a comprehensive medical exam. In cases where the weight loss is severe enough that the doctor suspects nutritional deficiency, they may ask you to adjust your diet or take a nutritional supplement even if an exact cause hasn’t yet been established.
Research from 2024 suggests that the most common causes of unexplained weight loss include cancer, digestive disorders, or psychiatric disorders. According to a 2017 study, the majority of people diagnosed with cancer after experiencing unexplained weight loss had pancreatic cancer or lymphoma. After that, kidney, bladder, and ureteral cancers were most common.