Hello Elizabeth, you haven t mentioned your height. Besides that loosing so much weight warrants an investigation for pathologic causes. What about your appetite? Do you eat at least 1500-1600 Kcal per day? Probably more would be needed to gain weight, depending on your physical activity. Are you healthy? Do you have any prolonged fever? Lymph nodes? Night sweating? Anything at all that seems abnormal to you? Your thyroid function (tachycardias, tremor, irritability etc)? Your spleen size? Diarrhea? Do you pass a lot of urine? A clinical encounter and appropriate laboratory investigation is important to identify possible causes. Thyroid dysfunction, parasites, malabsorption, infections, hematologic malignancies, diabetes (mellitus or insipidus) etc have to be excluded before giving diet advice. If there s nothing wrong with your health then perhaps this is your normal body weight. You could do some exercise and gain muscle weight but I think this is not going to make you feel any better because a muscular woman does not usually look so great. We can t change our genes. Just make sure you re eating the right amount of food and you re not hungry all the time. But do check for those pathologic causes first! I hope I ve addressed your concerns! If you need further or more specific guidance on this subject, please ask again. I ll be glad to provide it for you. Kind Regards!