A gf of mine was going through a similar thing recently and I suggested making up a lunch box of a night time and hiding all the unhealthy snacks. If she's having things like dairy & fruit then thats not really a problem, but if she's after sweet or salty snacks its best to keep them where they can't be spotted (like a cupboard other than the pantry) and make up a lunch box of a night time with all the snacks you want her to have and tell her thats all there is. It definitely works, and they feel pretty special to have their own lunch box and to also have choices iykwim?

Some options are, sliced meats, cherry tomatoes, fruit, carrot sticks, sultana's, cheese, yoghurt, dry cereals like cheerios, fruit, maybe 1 or 2 sweet/salty options and a sandwhich, some vegie pikelets/muffins or some mini quiches.

If she's a healthy eater try not to worry because she could be going through a growth spurt, and you'll probably find in a few weeks she may cut down and then you'll worry she's not eating enough LOL! Its up and down a lot, but its all perfectly natural.

Goodluck!

*hugs*
Cailin