my sister is losing weight significantly...she's getting really really skinny and everyone is concerned, even her. i know she doesnt have an ewating disorder, if anything she eats A LOT . a lot of junk food too... shes always eating mcDs and pizza. and i know she doesnt throw up.

the only exercise she does is walking from the bus stop to her school..or walking to the mall which is a few blocks away...she used to have big boobs and now shes very annoyed because theyre going away. is this just some freak of nature thing? what can she do to gain some weight? thanks!