Unexplained weight loss

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

The point at which unexplained weight loss becomes a medical concern is not exact. But many health care providers agree that a medical evaluation is called for if you lose more than 5% of your weight in 6 to 12 months, especially if you're an older adult. For example, a 5% 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 and overall health. Your ability to absorb nutrients from the food you eat also affects your weight. Economic and social factors also may play a role.

• Causes