Hi girlfriend! You must come from a family whose metabolism is in high gear! This could be a hereditary thing. Have you ever tried protein powder? Mix it two-three times a day with milk. The mcdonalds crap is no good for you! You need to be eating healthy! Lots of lean protein, vegetables, fruits and breads/grains!!! I know, sound like a mom huh? I am! In 4 years I will be 50, but I look 30! And I ate like i'm 20!!!!!!Life is good! Do you work out? Have you ever considered weight training? My husband and I love it. At least you are not fat with high blood pressure and other health issues! Hope i've helped some, at least I tried!!!!! Good luck sweetie!

Fairy godmother is right, just because you are very thin, don't go eating a bunch of crap. You can still have a heart attack ya know. Yeah, try those protein shakes and weight gainers and such that you can get at fitness and vitamin stores. If none of the above works, they do have prescription medications that will help you gain weight. Also, if not already on it, you could try birth control. It may sound silly, but along with a lot of other benefits, a lot of people gain weight when they first start taking it.