Eating anything that is NOT processed. Eating anything that is organic will help. Protein in your diet will help as long as you work out. The best thing you can do is NOT EVER worry about what the scale says... but be more concerned with how you feel in your clothes and what you think of yourself out of them. I am not trying to sound like a perv or anything.... I am just saying, You need to be concerned with how you FEEL and not what a scale says. You can also get input from the way people look at you.
eat good wholesome foods. No fast foods processed foods easy on sweets. Eat like a king in the morning like a prince at lunch and a pauper at dinner you'll be better off. exercise. Unless you're very under or very over don't worry to much sweety. you'll be fine. stay healthy.
because everyone's body is different i cant really specifically say what would work for you in a healthy way. but foods that are high in carbs and/or protein will help give you more 'meat on your bones' . you may think about seeing a nutritionist and they should be able to customize a diet that would help with your goal.