14 Reasons Behind Unexplained Weight Loss And How to Handle It

Have you lost weight on your initiative? It might be unnerving to lose weight for no apparent reason. You may be pleasantly surprised if you lose a few pounds naturally, but it could also indicate a health problem. If you suddenly lose more than 5% of your body weight within 6–12 months, consider it a warning sign that requires attention.

Numerous variables, ranging from mental health issues to digestive illnesses and hormone imbalances, might cause unanticipated weight shifts. Early cause detection may be essential for successful therapy and general health.

This article examines 14 possible causes of unexplained weight loss and offers helpful advice on how to deal with it. If you’ve seen a significant decrease in weight without making any lifestyle adjustments, consider speaking with a healthcare professional for a proper diagnosis and individualized treatment. Your health is worth the attention!

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What is Unexplained Weight Loss?

Every single one of us has an ideal Body Mass Index, the one our body corresponds to. Some can be over the mark, some under, and some in their ideal shape and size.

Unexpected weight loss is a noticeable reduction in body weight that occurs without any intentional effort. You’re not following a calorie-restricted diet, nor have you changed your eating habits or food intake. Additionally, your activity level has not increased.

Calorie consumption, level of activity, and general health all impact weight. Your capacity to absorb nutrients from the food you eat also influences weight. Social and economic variables might also be involved.

How Much Unexplained Weight Loss Is Bad?

Losing more than 5% of your body weight or more than 10 pounds over a period of six to twelve months, especially if you are over 65, is considered unexplained weight loss. Most people gain and lose a little weight daily, although these fluctuations usually don’t exceed five pounds. If, on the other hand, you have lost more than that without attempting, there may be another factor at play.

Every person’s rate of metabolism is different, but if your scale weight is consistently dropping, it is an alarming condition to look out for.

It is important to ensure that you consult a doctor for the same, and you might not even be aware of what is causing the rapid weight loss.

Read More: 6 Proven Strategies to Overcome Weight Loss Plateaus

Causes Of Unexplained Weight Loss?

Unexpected weight loss can have various causes but typically results from an underlying medical problem. Studies reveal that 72% of unexpected weight loss is due to an underlying medical issue. Unintentional weight loss, however, can also result from several lifestyle choices.

Some of the common underlying causes behind sudden unexplained weight loss include:

1. Loss of Muscle

Weight loss results from muscle atrophy, also known as muscle loss, which happens as the muscles contract.

Among the potential reasons for muscle loss are:

• Physical injuries from inactivity
• Neurological disorders, including multiple sclerosis, stroke, or amyotrophic
• Lateral sclerosis, as well as aging

Sarcopenia is the term used for age-related muscle loss. Scientists do not entirely understand why it happens.

2. Cancer

Loss of weight could be the initial indication of solid tumors like lung cancer (particularly lung adenocarcinoma), colon cancer, ovarian cancer, and pancreatic cancer, or blood-related cancers such as leukemias and lymphomas. Recurrence of an early-stage tumor (like breast cancer) can also result in weight loss.

Read More: Does Your Body Have a Set Weight? Understanding Set Point Theory in Weight Loss

3. Hyperthyroidism

Hyperthyroidism is the overactivity of the thyroid gland in the neck, and several illnesses can cause it. Among them are autoimmune conditions like Graves’ disease, which is the leading cause of hyperthyroidism in the US.

An overactive thyroid can also result from pregnancy, iodine exposure, and medication errors. Hyperthyroidism’s increased metabolism may cause weight loss.

4. Side Effects of Medication

Unintentional weight loss might occasionally be a side effect of medication your doctor recommended to address a medical condition rather than an indication of that illness.

Therefore, if you notice that you are losing weight after beginning a new medication, look for adverse effects, including nausea, vomiting, difficulty swallowing, appetite loss, and unexpected weight loss on the label.

If your weight loss is due to your prescriptions, a doctor can help you determine what needs to be done, whether changing to a different medicine or asking you to make dietary adjustments.

5. Problems with Substance Use

Unintentional weight loss may be more common in people who abuse addictive substances, including alcohol, tobacco, and recreational drugs. Certain addictive substances make eating unpleasant or reduce appetite. Maintaining a balanced diet is even more difficult for people with substance use disorders.

Problems with substance usage increase the likelihood of developing several illnesses. See your primary healthcare physician if you need assistance. They will assist in creating a treatment plan and listen without passing judgment.

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6. Addison’s Disease

An endocrine condition called Addison’s disease is linked to issues with the adrenal glands. These glands are located above each kidney and produce hormones essential for regulating metabolism, blood pressure, and stress response. They also produce imperative hormones or chemical messengers, such as cortisol. A deficiency of these hormones may cause fatigue, weight loss, and other symptoms of Addison’s disease.

7. Blood Abnormalities that may Result in Inexplicable Weight Loss

Blood is vital because it supplies all of your body’s cells with nutrition, water, and oxygen while also assisting in the fight against illness and infection. Unbalanced blood nutrition levels, however, can impact bodily functions and result in symptoms like inexplicable weight loss.

8. High Calcium Levels in the Blood

If you have hypercalcemia, you have too much calcium in your blood. Although overactive parathyroid glands in the neck typically cause high blood calcium, various medical supplements, drugs, and excessive calcium and vitamin D intake can also contribute to this condition.

Unexpected weight loss may result from digestive issues and weakening bones brought on by hypercalcemia. Additional symptoms include mood swings, kidney problems, and pain in the muscles and abdomen.

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9. Low Sodium levels in the Blood

Hyponatremia is the term for when your blood salt levels are abnormally low. Drinking a lot of water can cause your blood’s salt levels to drop, which is why this can happen. However, diarrhea, dehydration, and excessive alcohol consumption can also result in hyponatremia.

You won’t have any symptoms if your hyponatremia is minor. However, weariness, nausea, disorientation, muscle spasms, low blood pressure, and black urine could appear if your salt levels are too low.

10. Rheumatoid Arthritis

The autoimmune condition known as rheumatoid arthritis (RA) results in joint inflammation.

Even though two-thirds of RA patients are overweight or obese, according to the Arthritis Foundation, RA patients may also lose weight.

This weight loss could be due to the body using more energy due to the chronic inflammation associated with RA. Additionally, because the inflammation in their joints prevents them from doing regular exercise, patients with RA may lose muscle mass.

Some RA drugs can cause side effects like diarrhea and appetite loss, leading to weight loss in patients.

11. Lupus

Lupus is an autoimmune disease in which the immune system mistakenly attacks healthy cells. Lupus may also affect the digestive system and hamper the body’s capacity to absorb nutrients.

Another typical sign of lupus is appetite loss. Unintentional weight loss affects 17% to 15% of those with this illness, and patients usually experience weight loss before receiving a diagnosis.

Read More: How to Balance Macronutrients for Sustainable Weight Loss

12. Depression

Loss of appetite is often one of the first signs of depression. This may happen due to a lack of motivation to cook or a diminished interest in food. Depression can also affect the hormones that regulate hunger and fullness, leading to a reduced desire to eat.

13. Eating Disorders

It may appear that a friend or family member has lost weight for no apparent reason if they show signs of an eating disorder. Knowing what to do if you suspect someone of having an eating issue can be challenging, mainly if they refuse to discuss it.

Telling them you support them and encouraging them to receive the help they need are two of the most crucial things you can do.

14. Anxiety

Stressful life events, such as divorce, the death of a family member, or financial hardships, may cause weak appetites, meal skips, or less-than-usual eating. This can lead to unintentional weight loss. If stress affects your quality of life, seek assistance from friends or family or consult a mental health professional.

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Unexplained Weight Loss Treatment

When it comes to unexplained weight loss treatment, the possibility of understanding the condition is quite challenging and rare.

The underlying causes of unintentional weight loss determine the course of treatment. While you receive treatment for your ailment, your healthcare physician could advise you to work with a multidisciplinary team that includes a psychologist, occupational therapist, physical therapist, speech pathologist, dentist, and dietitian.

Your healthcare provider may suggest weight-gain drugs, dietary modifications, and nutritional supplements throughout treatment. Additionally, they could advise strength training rather than vigorous physical activity that encourages weight gain to assist you in regaining any lost muscle mass.

When to See A Doctor For Unexplained Weight Loss?

It’s not always safe to lose weight for no apparent reason. It’s time to take it seriously if you have lost 5% or more of your body weight without altering your diet or exercise regimen within 6 to 12 months. Rapid or ongoing weight loss may indicate an underlying medical problem that requires immediate care.

Keep an eye out for warning signs like:

• Extreme exhaustion that does not go away with rest.
• Appetite loss or trouble swallowing.
• Unexplained bleeding (blood in the cough, urine, or stool).
• Persistent discomfort or recurrent infections.

Early medical consultation can result in quicker diagnosis and treatment. To determine the underlying problem, your healthcare professional might suggest imaging scans, blood tests, or other assessments. Recall that prompt action can significantly impact how well you manage your health.

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Conclusion

If you lose weight for no apparent reason, your body may be attempting to tell you something. Early diagnosis is essential to finding and treating any underlying medical conditions. Identifying the symptoms and consulting a physician can avoid possible problems and guarantee prompt treatment.

It’s critical to trust your gut and pay attention to your body. If you have experienced noticeable weight loss without making any deliberate changes, don’t discount it. Make an appointment with a medical professional to discuss the cause and obtain individualized treatment.

Remember that you can achieve better results by being proactive about your health. Your well-being is essential. Do not be afraid to ask for help if something seems strange. One of the most empowering decisions you can make is to put your health first. Take control of your health journey by being knowledgeable, alert, and proactive.

• Feb 2019
  Written by Somapika D
• Apr 2025
  Edited by Ankita