What would you do if your 4 year old always says she hungry?

She is a tiny little thing she always says she is hungry but then she just picks at the food even if it what she asked for. And all she wants is potatoes. The only meat she eats is taco. But she does like eggs and cheese so she get protein. What to do with a picky eater that always says she is hungry. And no I will not make her finish all the food on her plate. Doing that is what makes people fat. So if you going to say that just keep it to yourself.