In their ongoing campaign for plain packaging of cigarettes, Action on Smoking and Health have dismissed fears of a slippery slope, saying:

Tobacco is not like any other product, it is the only legal product on the market which is lethal when used as intended... Plain packs for tobacco would not set a precedent for other products.

This is the same mantra we hear from self-described health campaigners every time the Trojan horse of tobacco is to used to expand state interference in lifestyle choices. Meanwhile, back in the real world, the latest issue of Nature provides the most shameless indication yet that policies once seen as unique to cigarettes will be applied to food and drink. In an article entitled 'The Toxic Truth about Sugar', three San Francisco-based public health advocates argue that sugar is a poisonous substance of abuse which is too readily cheap and too available. 75 per cent of all US healthcare expenditure is, they claim, spent on treating sugar-related diseases.

The seriousness of the journal precludes the possibility that it is a spoof, but one can still enjoy the moments of unintentional hilarity, as when the authors make this appeal to nature:

Evolutionarily, sugar was available to our ancestors as fruit for only a few months a year (at harvest time), or as honey, which was guarded by bees.

"Nature," they add, "made sugar hard to get; man made it easy." The millions of people who live in sugarcane-growing regions—for whom nature made wurzels hard to get—may raise a quizzical eyebrow at this, but even if it were true, anyone who understands medicine, as opposed to the nebulous and debased concept of 'public health', knows that nature is to be feared and defeated. Mother Nature brings us disease, malnutrition and infant mortality; mankind bring us vaccines, cures and plenty. Few doctors would recommend abstaining from fruit for months on end because Gaia has willed it, and even the most primitive religions do not regard bees as gatekeepers of unhealthy vices.

The authors note that infectious diseases now kill fewer people than "non-communicable diseases" and that more people are obese than are undernourished. Man's triumph over starvation and parasitic killers is a jolly good thing, but in the glass-half-empty world of public health, it only serves to show that government action is more urgent than ever. "Non-communicable disease"—what we die of if malaria and tuberculosis don't get us first—is set to be the medical establishment's buzzword of the 2010s. It covers all the ailments that have traditionally been beyond the remit of public health and it is so broadly defined as to allow almost any intrusion into our private lives.

Denmark already has a fat tax and many US states have some form of soda tax, but these are usually set so low as to be stealth taxes by any other name. Public health crusaders would like to go much further. The authors of the Nature article suggest banning the sale of sugary drinks to the under-17s, banning the advertising of sugary products on television, banning vending machines, removing sugar from the Food and Drug Administration's list of products which are Generally Regarded as Safe (GRAS), doubling the price of soda drinks, reducing opening times of shops that sell sugar-containing products and limiting the number of fast-food restaurants and confectioners that can operate in a district. "We’re not talking about prohibition," says Dr Laura Schmidt, one of the authors, "We're not advocating a major imposition of the government into people’s lives." One wonders how heavy the government's hand would have to be for Dr Schmidt to recognise a major imposition.

Libertarian objections to one side, fat taxes and soda taxes are phenomenally ineffective. A recent study found that a penny-per-ounce soda tax, as proposed in the Nature article, would reduce consumption by just nine calories a day. A 10% fat tax on milk and fizzy drinks, as proposed in the British Journal of Nutrition recently, would have even less effect.

Sin taxes of whatever variety are useless when set at low levels and spawn a host of unpleasant, unintended consequences when set at high levels. The repeated failure of such neo-prohibitionist policies will not be enough to deter the rampaging public health industry from taking an ever more draconian line on what we eat and drink. Governments, meanwhile, are so desperate for cash that the unholy alliance between taxman and puritan is only likely to get stronger.