What Causes Unexpected Weight Loss?

Unintentional weight loss is a reduction in your body weight that occurs when you are not trying to lose weight. It is defined as losing 10 pounds or 5% of your normal body weight over 6 to 12 months. Losing weight without trying can be a sign of a serious health problem, such as depression, cancer, digestive disorders, or stress. 

Older adults who experience unintentional weight loss are also at a higher risk of experiencing disease and death. Research estimates that up to 72% of older people who experience unintentional weight loss have an underlying health condition. If you're noticing that you've lost weight without meaning to, it's important to see your healthcare provider to learn the cause.

Reasons You're Losing Weight Without Trying

Several physical and emotional health conditions can lead to unintentional weight loss, and many of them require treatment. 

Mental health conditions that may cause a loss of appetite and lead to unexplained weight loss include:

• Depression: Feeling depressed may cause you to eat more or less than normal. It is estimated that one in six people in the U.S. experience depression at some point in their lives. 
• Anxiety: Anxiety often causes intense worrying and restlessness, but may also make you feel less hungry and eat less than normal.
• Stress: Stressful events such as a job loss or personal tragedy can lead to a change in your appetite and eating habits, which cause you to lose weight unintentionally. 
  

Physical health conditions that might also cause unexplained weight loss due to changes in appetite include:

• Cancer: A loss of appetite and weight loss are common symptoms of cancers that start in the blood like leukemia and lymphoma. Other cancers that may lead to weight loss include colon cancer, ovarian cancer, and pancreatic cancer. 
• Diabetes: People with type 1 diabetes may experience unintentional weight loss because their bodies cannot use sugar for energy properly. Other early symptoms of type 1 diabetes include increased thirst and frequent urination. 
• Chronic obstructive pulmonary disorder (COPD): COPD is a chronic lung condition that is often associated with poor nutritional status, as it may lead to a lower appetite and weight loss. 
• Neurological disorders: People with neurological (brain-related) conditions like Parkinson’s disease and Alzheimer’s disease often experience unintentional weight loss before they are diagnosed. This may be related to changes in their metabolism. 
• Hyperthyroidism: Hyperthyroidism (or an overactive thyroid) causes your metabolism to speed up. Over time, this leads to weight loss because your body is burning calories faster than normal. 
• Substance use: Using substances like amphetamines and cocaine causes a decrease in appetite and weight. This is also true for excess alcohol use. People who drink alcohol may experience liver disease, and this leads to problems with absorbing food and nutrients properly. 
  
• Celiac disease: People with celiac disease cannot tolerate gluten—a protein found in wheat. When exposed to wheat, their bodies have an autoimmune response that prevents nutrient absorption. This often leads to weight loss. 
• Chronic diarrhea: Long-term diarrhea causes weight loss and nutritional deficits. A variety of underlying health conditions such as ulcerative colitis or Crohn's can cause chronic diarrhea and affect your body's ability to absorb nutrients properly. 
• Lupus: Lupus is an autoimmune condition that causes problems with digestion and nutrient absorption. Weight loss is often an early symptom of lupus.
• Addison’s disease: Addison’s disease is an endocrine (hormonal) disorder that affects the adrenal glands, which can cause a loss of appetite, fatigue, and unexplained weight loss. 
• Rheumatoid arthritis: This condition causes pain and swelling in your joints. But, rheumatoid arthritis also causes inflammation in the digestive tract, which leads to problems with absorbing food and causes weight loss to occur.
  

Risk Factors for Unintentional Weight Loss

Certain factors can make also make you more likely to lose weight without trying. These risk factors include:

• Older age: Older adults have a higher risk of unintentional weight loss because of an increased risk of cancer and other chronic health problems.
• Dental problems: Having fewer teeth or lower saliva production can make eating difficult and lead to weight loss over time.
• Smoking: Smoking tobacco products that contain nicotine changes your metabolism and may increase the risk of weight loss. 

Medications may lead to several side effects that make eating and digesting food more challenging. Certain medications may cause the following side effects:

• Changes in taste and appetite: Medications like angiotensin-converting enzyme (ACE) inhibitors, antibiotics, and selective serotonin reuptake inhibitors (SSRIs) can make food taste bad and decrease your appetite, causing you to eat less.
• Dry mouth: Antihistamines and diuretics are examples of medications that may decrease the amount of saliva in your mouth. This makes chewing and swallowing food harder. 
• Nausea: Several medications including antibiotics, SSRIs, and blood pressure medications can make you feel nauseous and decrease appetite. 

When to Contact a Healthcare Provider

Unintentional weight loss may often be the result of an underlying health condition. If you notice drastic changes in your weight without trying, it's important to see your healthcare provider soon. The general rule of thumb is if you've lost 10 pounds or 5% of your usual body weight without trying, schedule an appointment with your provider. If you lose a large amount of weight quickly, call your provider and ask if you should go to the emergency department for prompt diagnosis. 

Diagnosis

To determine the cause of unintentional weight loss, your healthcare provider may conduct several diagnostic tests. When you see your provider, they will likely perform a physical exam and ask about your medical history. Your provider may also inquire about how much weight you have lost and how much time it took for you to lose the weight. They will also ask about your eating habits, workout routines, stress levels, recent illnesses, medication use, and any dental problems that you're experiencing. 

Because the cause of unintentional weight loss can vary greatly, the exact diagnostic tests you need will depend on your symptoms and overall health status. But your provider may recommend one or more of the following tests to help determine the cause of your weight loss:

• Blood tests: Check your complete blood count (CBC), metabolic panel, liver function, thyroid function, C-reactive protein count, erythrocyte sedimentation rate, and glucose levels to assess which chronic health condition is causing your weight loss
• Urine test: Diagnoses certain infections or chronic conditions
• Fecal occult blood testing: Tests for blood in the poop (stool) to look for signs of digestive disorder that affect your ability to absorb nutrients
• Imaging tests: Use ultrasound, X-ray, or MRI to examine your internal organs (such as your brain, intestines, or liver) to check for signs of underlying health conditions that may contribute to unintentional weight loss
• Psychological evaluation: Screens you for mental health conditions that may be changing your appetite levels

If all of your tests come back normal and there isn't a clear cause of your weight loss, your provider may recommend close monitoring of your symptoms and condition for three to six months. 

How to Treat Unintentional Weight Loss

The treatment for unintentional weight loss depends on the underlying cause. Your healthcare provider may recommend working with a multidisciplinary team that includes a dentist, dietician, speech pathologist, occupational therapist, physical therapist, or psychologist as you receive care for your condition.

During treatment, your healthcare team may recommend dietary changes, nutritional supplements, and medications for weight gain. They may also recommend participating in less rigorous physical exercise that promotes weight gain and instead suggest strength training to help you rebuild any muscle mass you've lost.

If your unintentional weight loss is due to a loss of appetite, your care team may suggest:

• Stopping any medications that cause a lack of appetite
• Incorporating your favorite foods into your diet
• Working with a dietician or nutritionist to find a meal plan that works for you
• Meeting with a mental health provider to reframe your thoughts about food

How to Prevent Unintentional Weight Loss

It might not always be possible to prevent unintentional weight loss. When you lose weight unintentionally, it may be a sign of a serious health problem that needs proper attention and care. However, if you notice that a new medication is causing changes in your weight and appetite, it's important to let your provider know so they can adjust your treatment plan.

A Quick Review

Unintentional weight loss occurs when you lose body weight without trying. It is defined as losing 10 pounds or 5% of your normal body weight over 6 to 12 months. Unintentional weight loss may be caused by a serious health problem such as cancer or an autoimmune disorder. Other possible causes include depression, stress, digestive system disorders, and drug side effects. If you're experiencing weight loss without trying, see your provider for treatment to reduce the risk of complications.