According to a Reuters report, a new study from the United Kingdom estimates that more than 3,000 lives would be extended if the 17.5 percent value-added tax was imposed on supposedly unhealthy foods. Without endorsing the specific estimates, the underlying economic analysis is sound. Certain foods presumably are unhealthy (at least for people who already are overweight) and taxing those foods will change behavior (just like taxing work, saving, and investment changes behavior).

But this does not mean, as a matter of principle, that the government should use the tax code to dictate private choices. Once politicians wander down that path, what will stop them from taxing people at higher rates if they don’t jog at least three times a week? Or how about tax credits for eating green vegetables? Some might respond that taxpayers have a right to insist on healthy behavior since they are paying – via the government-run health care systems – the medical costs of unhealthy people. But this highlights the problem of a socialized health care system. If people are responsible for the consequences of their own choices, then there is less temptation for nanny-state policies. For what it’s worth, this does not mean that the U.K. should maintain a VAT exemption for food. But the exemption should be eliminated as part of a plan to reduce the general tax burden, not as a scheme to control people’s lives:

A “fat tax” on salty, sugary and fatty foods could save thousands of lives each year, according to a study published on Thursday. Researchers at Oxford University say that charging Value Added Tax (VAT) at 17.5 percent on foods deemed to be unhealthy would cut consumer demand and reduce the number of heart attacks and strokes. The purchase tax is already levied on a small number of products such as potato crisps, ice cream, confectionery and chocolate biscuits, but most food is exempt. The move could save an estimated 3,200 lives in Britain each year, according to the study in the Journal of Epidemiology and Community Health. …Any “fat tax” might be seen as an attack on personal freedom and would weigh more heavily on poorer families, the study warned. A food tax would raise average weekly household bills by 4.6 percent or 67 pence per person. Former Prime Minister Tony Blair has previously rejected the idea as an example of the “nanny state” that might push people away from healthy food.