special subjects
Involuntary Weight Loss
Causes of Involuntary Weight Loss
Most often, weight loss occurs because people take in fewer calories than their body needs. They may take in fewer calories because their appetite has decreased or because they have a disorder that prevents their digestive tract from absorbing nutrients (called ). Less often, people have a disorder that causes them to use more calories (for example, an overactive thyroid gland). Sometimes, both mechanisms are involved. For example, cancer tends to decrease appetite but also increases caloric expenditure, leading to rapid weight loss. Almost any long-term illness of sufficient severity can cause weight loss (for example, severe heart failure or emphysema). However, these disorders have usually been diagnosed by the time weight loss occurs. This discussion focuses on weight loss as the first sign of illness. Causes can be divided into those in people who have increased appetite and those in people who have a decreased appetite. Withincreased appetite,the most common unrecognized causes of involuntary weight loss are An overactive thyroid gland ( Hyperthyroidism ) Uncontrolled Diabetes Mellitus (DM) None Disorders that cause Overview of Malabsorption None Withdecreased appetite,the most common unrecognized causes of involuntary weight loss are Emotional disorders (for example, Depression ) Overview of Cancer None None None 