There are many other causes for weight loss such as worms in stool, depression, anorexia nervosa, cancers especially colon cancers (unlikely because of
her age), infections and loss of
appetite. Loss of
appetite can again be due to certain medications, drug abuse, depression, acute and chronic infections, eating disorders, cancers and hypothyroidism. It could also be due to increased metabolism as in hyperthyroid states, cancer etc.