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

Your body weight is determined by your calorie intake, overall health, age, nutrient absorption and other factors. After you reach middle adulthood, your weight should remain relatively stable from year to year, although a decrease of a few pounds is rarely cause for concern.

Unexplained weight loss of 10 pounds (4.5 kilograms) or more, weight loss of more than 5 percent of your body weight, or persistent weight loss should be investigated.

Aug. 20, 2011