For centuries, no medical cure was complete without it. It was regarded as the ultimate health food. Quarrelling doctors, who couldn't bring themselves to agree about anything else, concurred in praising it as an ideal treatment for almost all kinds of sickness, as it fortified the patient, aided digestion and balanced the humours. Miraculously, it also made people feel better, and encouraged them to take drugs that would otherwise be too bitter. It strengthened the infirm and nourished women after childbirth. The name of this health-giving wonder was sugar.
Has any other foodstuff undergone such a total switch in status? Once a cure-all, it is now a kill-all. Sugar is blamed for almost all of the dietary ills of the western world and castigated as "empty calories". Obesity, diabetes, heart disease, dental problems and depression have all been linked to sugar consumption.
The food historian Reay Tannahill mentions one expert of the 1980s who associated eating sugar with gallstones, appendicitis, ulcers, diverticular disease and cancers of the lower gut. Opinion seems virtually united: sugar is lethal. The Sugar Addict's Total Recovery Programme, published earlier this year, compares "addiction" to sweets with addiction to heroin.
Yet in previous ages, as Tim Richardson describes in his Sweets: a history of temptation (Bantam Press, £15), sugar was "one of life's unequivocal Good Things". In the Middle Ages, Europe had inherited the Arab habit of mixing medicinal herbs with sugar, whether in the form of syrupy concoctions, soothing linctuses, jellies, sherbets or calming lozenges. Sugar was certainly a treat, but a health-giving one. In the earliest French recipe book, the Viandier of Taillevent, all the sugared dishes are specifically marked as being good for the sick or weak. Pierre Pomet, in A Compleat History of Druggs (1712), recommended candy for "Rheums, Coughs, Colds, Catarrhs, Asthmas, Wheezings etc". In early modern times, when people wished to say that something was unthinkable or absurd, they spoke of it being "like an apothecary without sugar".
In fact, as Richardson points out, we still use confectionery in the pharmacy, though we are no longer so open about doing so. Almost all medicines for children now come in sickly sugar-free varieties, laced with fruity flavourings and artificial sweeteners whose effects on health are yet to be gauged. But we still take sugared pastilles for our coughs, and "many of the leading brands . . . are now made by major sweets and chocolate manufacturers, including Mars". Athletes spend large sums on sugary "isotonic" drinks and tablets, whose packaging is careful always to use the word "glucose" in place of sugar.
We do seem to be in a muddle about sugar. The hypocrisy of earlier centuries was to love as morally spotless a substance procured by slavery. But the hypocrisy of our own is pretending not to love something that we guzzle in ever-increasing quantities. A recent study from Bristol University showed that British children now consume 25 times as many sweets as in 1950, and 30 times as many sugary soft drinks. Someone must be providing the money to buy this smorgasbord of carbohydrates. Who it is, though, is a mystery, because most parents declare themselves mortal enemies of sugar, even as they heap child-appeasing soft drinks into their trollies.
The trouble with modern sugar consumption is not least that huge amounts of it are barely enjoyed. When you drink a bottle of Sprite, you ingest spoonfuls of hidden sugar without even noticing. Whereas when you eat a fresh Bath bun, whose sugar is proudly out in the open, sparkling and white, every crystal of sweetness gives pleasure. Perhaps if we didn't hate sugar so vehemently, we wouldn't ruin our teeth eating so much of it.