Also, if you keep changing up foods so often and never offer them to her as staple items she may be waiting for you to "jump through hoops" so to speak for her meals. I'd make the things you like to make and the things kids generally like to eat, limit her milk a bit and offer her water or something less filling if she's thirsty and just continue offering foods when you or the rest of the family eats and if she eats it, great, if not, then oh well. I wouldn't make a huge deal, I wouldn't offer her rewards or anything special, I wouldn't offer her other foods, as a matter of fact, if you offer her lunch and she doesn't eat it, you can offer her the SAME thing at dinner that night. Just wrap and store in the fridge, reheat later and that's it. Don't drive yourself nuts. If she's liked it before she'll probably like it again IF she realizes that that is what her choice is.
Has she always eaten like this? If she has no health issues, she will regulate how much food she needs as long as you are consistent and offering a balanced variety of foods.
Also, steer clear of too much snacking. If she doesn't eat "meals" and is getting a hold of snacks throughout the day she will be less hungry for meals.