My kids (4.5 and 6) were KoolAid Junkies and I hated it....one day my son asked me why I drink so much water. I saw this as an opportunity to teach him something so I told him.
"well what happens when the outside of our bodies gets into a bath tub of water?"
of course he answers "we get clean"
I then said "well this is why I drink water, the clean clear water gives all my insides a bath. My heart and tummy and brain and everything that helps mommy be a good mommy gets all nice and clean when I drink this water. It gives me an inside bath."
He thought about it for a while and the next day when he had lunch he asked for a bottle of water instead of Kool Aid. My daughter followed suit and now they both drink MAYBE one glass of KoolAid and the rest is either milk or water.
Water, its scrubadub for your insides......