The doctor and nutritionist are fit you to talk to, not your little girl. YOU talk to these knowledgeable professionals about how to take care of your child. You should do the same thing for your whole family. Don't ever single her out because she's a little fatter. At this rate you can end up spending the next 8 years trying to "fix" her. By then she could develop other issues.
Talk about healthy choices to everyone. Don't look at scales or body shapes.
Tell her she's beautiful.