Tuesday, May 26, 2009
Articles in the New England Journal of Medicine on April 30, and in the New York Times on May 19, discuss a proposal now before Congress to impose a tax on sugar-sweetened sodas in order to reduce obesity. Taxes are ordinarily intended to raise revenue, but some taxes, such as taxes on alcohol and tobacco--and on carbon emissions, should such a tax ever be passed--are designed not to raise revenue but to alter behavior, and the more they succeed in altering behavior the less revenue they generate. ...
[T]here are two situations in which preventing people from choosing the style of life that maximizes their utility can be defended (provided certain assumptions are made about cost and efficacy) on economic grounds. One is where consumers are unable to evaluate a product or to act upon their evaluation; another is where a voluntary transaction imposes costs on other people which the transactors do not take into account.
The first is a significant factor in the soda market. The sellers advertise very heavily to children, who do not have the knowledge or the self-control that they would need to be able to resist such advertising. ... The solution, though, is not a tax on sodas, as such a tax would have only a small effect. A ban on advertising would be preferable. ...
As to whether by increasing obesity the sale of sugar-flavored sodas imposes costs on other people besides the buyers, the evidence is mixed. ... [A]ssuming nevertheless that the net social costs of obesity are positive, this would be a ground for arguing for taxing obesity, but such a tax would be unacceptable as well as cruel. The alternative of a soda tax would be unlikely to have much effect, for the reasons stated earlier.
To combat obesity, an article in the April 30, 2009 New England Journal of Medicine by Brownell and Frieden argues for a tax on sugared beverages. I agree with Posner that this is a bad idea.
Many doctors and others who advocate taxing sugared beverages and fast foods at heart do not believe that consumer taste for sugar and fast foods should be taken into account in devising public policy. Perhaps not, but they have to advance better arguments than they have done so far to justify policies that interfere with the exercise of these tastes and desires.