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.

If you're losing weight without trying and you're not sure why, consult your doctor — especially if you lose as much as 10 pounds (4.5 kilograms) or 5 percent of your weight within six to 12 months. Your doctor will work with you to determine what's causing the weight loss and the best way to treat the problem. You may need a special diet to prevent further weight loss or to regain lost pounds.

Aug. 20, 2011