What is Weight Loss?

Unexplained weight loss, or losing weight without trying — particularly if it's significant or persistent — may be a sign of an underlying medical disorder.

The point at which unexplained weight loss becomes a medical concern is not exact. But many doctors agree that a medical evaluation is called for if you lose more than 5 percent of your weight in six months to a year, especially if you're an older adult. For example, a 5 percent weight loss in someone who is 160 pounds (72 kilograms) is 8 pounds (3.6 kilograms). In someone who is 200 pounds (90 kilograms), it's 10 pounds (4.5 kilograms).

Your weight is affected by your calorie intake, activity level, overall health, age, nutrient absorption, and economic and social factors.

Causes

Unexplained weight loss has many causes, medical and nonmedical. Often, a combination of things results in a general decline in your health and a related weight loss. Sometimes a specific cause isn't found.

Usually, an unrecognized cancer will have other symptoms or abnormalities of laboratory tests, in addition to unexplained weight loss.

Potential causes of unexplained weight loss include:

1. Addison's disease (adrenal insufficiency)
2. Cancer
3. Celiac disease
4. Changes in diet or appetite
5. Changes in sense of smell
6. Changes in sense of taste
7. COPD (chronic obstructive pulmonary disease)
8. Crohn's disease (a type of inflammatory bowel disease)
9. Dementia
10. Dental problems
11. Depression (major depressive disorder)
12. Diabetes
13. Heart failure
14. HIV/AIDS
15. Hypercalcemia
16. Hyperthyroidism (overactive thyroid)
17. Hypothyroidism (underactive thyroid)
18. Medications
19. Parkinson's disease
20. Peptic ulcer
21. Substance abuse (alcohol, cocaine, other)
22. Tuberculosis
23. Ulcerative colitis (a type of inflammatory bowel disease)