Saw this idea on FB 
If your children ask you all day long for snacks then maybe give it a go ........
Fill a small plastic box with different snacks one box per child, filled each day and they can choose how much of it they eat per day BUT when it is gone it is gone, nagging or whining won't get them anything extra
You decide what goes in the box, how much and what sort of things
If they eat it all before 10.30am then their choice but no more snacks, obviously lunch and dinner are under your control, certainly for little ones, but if they have sandwiches for lunch then I guess the whole day's food until tea/supper/dinner could be put in box if you want, up to you
It can be as healthy or not as you like
It gives you complete control on what goes in the box but also gives the children some control too on what they eat when in whatever order they choose
I guess you could say they have until 5pm (or whatever time you decide) to eat from the box so that they don't spoil appetite for tea/supper/dinner
My DS is grown up now but think this could be really deffo brill idea for those with younger children if they just keep asking all day for snacks