There is something about the experience of consuming sugar and sweets, particularly during childhood, that readily invokes the comparison to a drug. I have children, still relatively young, and I believe raising them would be a far easier job if sugar and sweets were not an option, if managing their sugar consumption did not seem to be a constant theme in our parental responsibilities. Even those who vigorously defend the place of sugar and sweets in modern diets – "an innocent moment of pleasure, a balm amid the stress of life", as the journalist Tim Richardson has written – acknowledge that this does not include allowing children "to eat as many sweets as they want, at any time", and that "most parents will want to ration their children's sweets".

But why is this rationing necessary? Children crave many things – Pokémon cards, Star Wars paraphernalia, Dora the Explorer backpacks – and many foods taste good to them. What is it about sweets that makes them so uniquely in need of rationing?

This is of more than academic interest, because the response of entire populations to sugar has been effectively identical to that of children: once people are exposed, they consume as much sugar as they can easily procure. The primary barrier to more consumption – up to the point where populations become obese and diabetic – has tended to be availability and price. As the price of a pound of sugar has dropped over the centuries, the amount of sugar consumed has steadily, inexorably climbed.

In 1934, while sales of sweets continued to increase during the Great Depression, the New York Times commented: "The Depression (has) proved that people wanted candy, and that as long as they had any money at all, they would buy it." During those brief periods of time during which sugar production surpassed our ability to consume it, the sugar industry and purveyors of sugar-rich products have worked diligently to increase demand and, at least until recently, have succeeded.