Unintentional Weight loss is defined by a 5% reduction of usual body weight over 6-12 months. It is associated with increase mortality rates. The most common cause of unintentional weight are increased expenditure or reduced dietary intake.

Unintentional weight loss should away raise suspicion of malignancy. Other non malignant causes can be due to maldigestion or malabsoprtion, endocrinopathies, psychiatric conditions or medications.