Rebellion for a young diabetic all comes down to control. They want some. Especially in a world where they seem to have none.
They're being controlled in what they eat, what they can do, what they can drink. Virtually their entire life is turned upside-down due to this disorder.
So they rebel.
Food seems to be the one area where young diabetics rebel first. This can either be two-fold: they refuse to eat or they sneak/horde food. Both can be dealt with easily enough, but you need patience. Remember, we're talking about control here. If the diabetic perceives they're more in control, the less apt they are to rebel.
Refusing to eat can be dealt with simply making something they like. You need to be reasonable, of course. You just can't let them eat chocolate cake all they want. Our oldest son has never liked mashed potatoes. So, whenever mashed potatoes are on the menu, we make him a baked potato--which he likes. Go figure.
Sneaking and hording food is a bit more difficult, as you have to be constantly vigilant. As our son's dietician said to us, "Feed him until he's full." So, we feed him until he's full. Then, when we catch him not sneaking food, we praise him. We remind him if he does. It's difficult not to get angry, especially when you're on a strict budget. Ask your dietician for ideas on how to make your little one more full.