Unexplained weight loss and an increased appetite may be symptoms of an endocrine disorder such as diabetes mellitus or an overactive thyroid gland. They may also indicate the presence of a malabsorption syndrome such as Crohn's disease or a mental health condition such as compulsive exercise. You should see a doctor anytime you experience unexplained weight loss, as this symptom may signify a serious underlying medical problem.
Endocrine Disorders
Unexplained weight loss in combination with sustained or increased appetite may indicate that you have an endocrine disorder such as hyperthyroidism or type 1 diabetes. With hyperthyroidism, unexplained weight loss coupled with an increased appetite result from increased energy expenditure and rapid digestion, whereas with uncontrolled diabetes, weight loss occurs due to increased urination and the body's inability to use glucose for energy. Besides weight loss and increased appetite, some other symptoms of hyperthyroidism include rapid heartbeat, irritability, nervousness and more frequent bowel movements. Other symptoms of type 1 diabetes include increased thirst, fatigue, blurry eyesight and tingling or numbness in the feet.
Malabsorption Syndromes
Malabsorption syndromes -- conditions in which your small intestine cannot metabolize nutrients from food -- may also cause weight loss, despite an increased appetite. After cancer, non-malignant gastrointestinal conditions such as malabsorption syndromes are the next most common cause of unexplained weight loss, according to a 2007 article published on HCPLive -- unlike cancer, however, malabsorption syndromes may cause appetite to increase, rather than decrease. Some malabsorption syndromes include: celiac disease, Crohn's disease, Whipple disease and even lactose intolerance. The presence of diarrhea with weight loss and increased appetite is a strong indicator of a malabsorption syndrome. Bloating, gas, abdominal pain and mood disturbances may also accompany a malabsorption syndrome.
Psychological Causes
Your mental health can also affect your weight and appetite. Conditions like anxiety, stress and depression may cause unexplained weight loss and increased appetite. In particular, compulsive exercise -- also called obligatory exercise and anorexia athletica -- can cause weight loss with an increased appetite, especially if the calories burned through exercise are not replaced. Compulsive exercise often goes hand-in-hand with eating disorders, such as anorexia or binge eating, which affect both weight and appetite. Some signs that you may be exercising compulsively include experiencing guilt or anxiety if you skip a workout and putting exercise before friends, family and other obligations.
When to See a Doctor
It is important to see a doctor if you have any unexplained weight loss, especially if you unintentionally lose as much as 10 pounds, or 5 percent of your body weight, in six to 12 months, according to MayoClinic.com. Your doctor will evaluate your symptoms and, if necessary, conduct diagnostic tests to determine the cause of your unexplained weight loss and increased appetite. Depending on the cause of your weight loss, your doctor may prescribe a special diet or medication to regain lost pounds and prevent further weight loss.
References
- HCPLive; The Many Causes of Involuntary Weight Loss: a 3-step Approach to the Diagnosis; Mark G. Graham, MD, and Barbara Knight, MD; May 2007
- MayoClinic.com; Hyperthyroidism: Symptoms; December 2010
- MedlinePlus: Type 1 Diabetes
- MedlinePlus: Celiac Disease
- Johns Hopkins Children's Center: Malabsorption
- KidsHealth: Compulsive Exercise
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