There are many other causes of unexplained weight loss like worms in stool, depression, anorexia nervosa, AIDS, cancers especially colon cancers, drug abuse, infections
and loss
of appetite. Loss
of appetite can again be due to certain medications, drug abuse, depression, AIDS, acute and chronic infections, cancers and hypothyroidism. Either she does not eat well or there is increased metabolism as in hyperthyroid states, HIV, cancer etc.