I would suggest not giving her less of anything, but MORE of green vegs etc.
So all kids get the same portion of protein and carbs and just don't have any leftovers of those, HUGE pile of veg though.
My boys are both big eaters, they eat until they are full but they fill up on veg.
So a normal dinner plate will have say a small steak, a small scoop of mash and an absolute mountain of broccoli, carrots, peas, etc.
Seems to work, for my two the main thing is that there is a lot of it and that it is right in front of them, they aren't actually too concerned with what it is made up of.
My 6 year old just had breakfast, he had one slice of really seedy/nutty toast with plenty of real butter and vegemite, half a punnet of cherry tomatoes, some blueberries, a piece of cheese (about matchbox size), a banana and a glass of unsweetened almond milk.
It is a lot easier for everyone this way, they need to eat a lot, I need to feed them a lot (I grew up very poor and was often hungry so have my own demons there) and they need to eat well and maintain a healthy weight. They probably chomp through 10+ servings of fruit and veg a day.
DH is cooking dinner tonight as I am out, the plan is pasta in garlic butter (but a small bowl) accompanied again by a big bowl of salad so they can get the volume and nutrients without excess calories.