8 kgs for a 2-year-old baby girl is good. You need not worry. While growing up, children tend to lose their appetite and be very selective towards what they want to eat or not. Iron/ multivitamin supplements at this early stage is something that I would not recommend as we should try to feed childre....
Take high fiber low fat diet. Drink lot of water everyday. Take small and frequent meals at regular intervals of 2-3 hrs. Avoid outside food. Ask me directly for customized diet plan for you.