I don't allow the children to say eeeww, I hate that, that's gross, ect because it gets the others ones on the same bandwagon. If a child said to me " I hate that when's snack and what is it?" I would tell them snack looks exactly like lunch but if the lunch is all gone then it will be something really yummy". And if the child ate the lunch I would make sure the snack was that child's favourite if they didn't eat the lunch then I would follow through. It wouldn't take long for that child to start eating without the fuss. However it's the fuss at home that works and that's why they are picky eaters.
Picky eaters are created not born !