Just a suggestion- just make sure what she does eat is filling ie protein rich foods (eggs, cheese etc) and high in complex carbs- whole grains (grainy bread, weetbix etc)
Try just giving her three meals a day with nothing in between and at set times say 8am , 1 pm and 6pm. Of course give her food in between if she asks or is hungry but don't offer it so that you establish a set meal time each day. Put the food on a plate, at the table and sit and eat yours with her. If she eats it, she does, if not, take it away and don't offer anything else.
Maybe allow just one cup of milk at night after dinner and before bed and no fruit juice as it is filling and puts chn off their food.
If after a few days (of set meals times and no grazing all day) she is still not eating (and record everything she does eat and amounts) I would take her to a naturopath, homeopath or dietician as she make need something to stimulate her appetite?
Hopefully if you try the plan she will naturally get hungry and food won't be an issue all day for you as you try and get some into her! At creche she prob knows its meal time and this is the opportunity to eat as food isn't continually offered at other times.
Just something for you to ponder....