Unintentional Weight Loss: 6 Possible Causes

Unintentional weight loss is defined as a noticeable decrease in body weight that occurs without the individual actively attempting to lose weight. If a person is eating the same diet and has not increased their physical activity, unexpected weight loss may indicate underlying health issues. In some cases, unintentional weight loss can be highly concerning when the person loses a significant amount of weight within a short span. The British Medical Journal's Best Practice report defines unintentional weight loss as a loss of at least 5% of a person's usual body weight within the past 6 to 12 months, which is not expected as a result of treatment for a known illness.

Unintentional weight loss: Know possible causes

There can be several possible causes of unintentional weight loss. Here are some of these:

1. Medical condition

Various health conditions can lead to weight loss, including:

Cancer: Many types of cancer can cause metabolic changes and loss of appetite.

Hyperthyroidism: An overactive thyroid can increase metabolism, leading to weight loss.

Diabetes: Uncontrolled diabetes can cause weight loss due to the body's inability to properly utilize glucose.

Gastrointestinal disorders: Conditions like Crohn's disease, celiac disease, or ulcers can impair nutrient absorption.

While these are some common causes, many other health conditions may contribute to unintentional weight loss.

2. Mental health issues

Maintaining mental fitness is crucial for overall well-being. Conditions such as depression and anxiety can significantly impact appetite and eating habits, potentially leading to eating disorders in some individuals.

3. Certain medications

Certain medications, including those for depression, cancer, or chronic illnesses, may have side effects that reduce appetite or cause nausea. Poor eating habits then further contribute to weight loss.

4. Chronic infections

Infections such as tuberculosis or HIV/AIDS can lead to rapid weight loss due to increased metabolic demands and decreased appetite. Medical intervention is crucial in these cases.

5. Increased physical activity

Unintentional changes in routine or increases in physical activity without a corresponding increase in caloric intake can also result in weight loss.

6. Elderly age

Weight loss is common among older adults due to factors such as changes in metabolism, dental issues, or alterations in appetite.

Unintentional weight loss is not always a sign of good health. If someone is experiencing such weight loss, it is important for them to consult a healthcare professional to identify the underlying cause and receive appropriate treatment.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.

References

Assessment of unintentional weight loss: BJM Best Practice. 2025.