Mei
Try to make her runs or do all sort of kids exercise, I think it will increase her appetite. Instead of rice and marcoroni try other fingers food, like chicken/fish nuggets. Don't know if it works, keep trying lar..
Another possibility.. is she teething? Because I just recalled that she has fewer teeth than her normal age should has. If that is the case, she might be suffering from gum pain because of the teething problem.