If young children are not extremely sensitive to carbs they can usually tolerate lot more carbs: i.e. LC parents who can't tolerante bananas have LC children who can eat two bananas a day without complaint.
So young children diet can be higher carbs without negative consequences.
BUT if the young children we're talking about are very carb sensitive with a tendency to irregular blood glucose, moodiness, depression, nightmares and so on then you can actually go very low without conseguence.
I have known hypoglycemic kids who couldn't eat more than 30 grams of carbs a day but grew healthy and without problem. Hypoglycemic kids have been following low carb diets even before they became fashionable.
For example Vincent was an 8 year old who would eat everyday a very LC diet of sardines, bacon, hamburger, cream cheese, chicken, salad, eggs and steak in order to control his hypoglycemia.