The addiction to sugar is more powerful than to cocaine, I have read that in many studies carried out over the last two decades. How is this possible, well, the parents already have “sugar” in their genetic code, heh, heh, heh, heh. When the child is born, the first foods contain glucose; in other words, we are sugar consumers from the moment we are conceived.
Nowadays, the foods we eat, genetically processed, provide 200 times more gluten, hence the reason for the intolerance of many children to consume them and for us adults to suffer from diabetes, high blood pressure… And for this reason, psychologists have found no remedy and classify gluten-intolerant children as “autistic”.
It is true that many parents use sweets as a way of reassuring their children, as @videoaddiction claims, but this is not entirely true. I can't give my son any sweets after 3pm, as it's 1am, and he's still hyperactive; the sugar, instead of calming him down, energises him so much that he becomes a train wreck.
At least not here. My daughter is gluten intolerant, but they don't classify as autistic. She is also sensitive to lactose. These things might decrease as she ages.
I think the point of the "calm down" was not in the physical sense, but more as a way to pacify the child, keep them occupied and "happy" in the moment, even though later, they will likely crash and become terrors. :)
There are studies about how obesity at time of conception passes a fat gene of some sort. Will look for the study later. It is interesting.