NOTTINGHAM, England -- A "fat tax" on unhealthy food could reduce cardiovascular disease -- but only if it was very carefully targeted, researchers here said.
NOTTINGHAM, England, July 12 -- A "fat tax" on unhealthy food could reduce cardiovascular disease -- but only if it was very carefully targeted, researchers said.
In a mathematical model based on British data, a fat tax levied on unhealthy foods could avert about 2,300 deaths a year in the United Kingdom, according to Oliver Mytton, M.D., of Queen's Medical Centre, here.
The benefit would come mainly from reducing salt intake, Dr. Mytton and colleagues reported in the August issue of the Journal of Epidemiology and Community Health.
But another model -- in which the target was foods high in saturated fats -- showed that a fat tax might actually increase cardiovascular deaths, the researchers said.
"Taxing foodstuffs can have unpredictable health effects" if all the supply and demand interactions aren't taken into account, Dr. Mytton and colleagues said.
In the U.K., a value-added tax of 17.5% is already levied on confectionery, ice cream, savory snacks, and most drinks.
Extending the tax selectively has been proposed as a way of slowing the growth of obesity and promoting healthy food choices, the authors said.
In the U.S., the idea has been dubbed the "Twinkie tax" and first gained widespread attention in 1994 when Yale University professor Kelly Brownell, Ph.D., proposed it in the New York Times.
Among other things, Dr. Brownell noted, a tax of just a penny on every soft drink sold would net .5 billion a year in revenue that could be used to promote better nutrition.
Since then several states -- including Arkansas, Tennessee, Virginia and Washington -- have levied "fat taxes" on soft drinks and other states have also tested the idea. But by 2006, all of the taxes had been repealed.
The British researchers looked at three approaches to a fat tax in the U.K.:
In the first case, the researchers said, consumers would probably reduce their intake of saturated fats, but at the same time would reduce polyunsaturated and monounsaturated fats and slightly increase salt intake.
That could actually result in an increase in cardiovascular deaths, they said.
The second approach uses the SSCg3d score, a validated measure of the "healthiness" of a food, in which foods with a score of nine or greater are regarded as unhealthy.
The scale adds up points for factors such as energy density, sodium content, and saturated fat and then subtracts points for such factors as calcium and iron content. On the scale, for instance, spinach scores minus 12, while some chocolate cookies score +29.
Using that approach, a tax might prevent 2,300 deaths a year in the U.K, the researchers said.
The "best outcome" combination of the SSCg3d score and taxes on selected other foods could avert as many as 3,200 cardiovascular deaths in the U.K. per year -- a 1.7% reduction, they said.
The researchers cautioned, however, that food purchases are relatively insensitive to price changes, and a taxation rate of 17.5% is likely to reduce the intake of nutrients such as salt and saturated fats by no more than 5% to 10%.
"The scope for significantly altering the national diet by judicious use of [a value-added tax] seems limited," they said.
They also cautioned that the findings should be interpreted carefully, because of several limitations, including the relative crudity of the data and the inability to characterize other possible health effects. They pointed out that the study was limited to the effects of dietary fat and salt on cardiovascular disease and does not take effects of other nutrients into account.
They also noted that extending the findings to other countries is "inappropriate" since consumers there may behave differently than in the U.K.
Indeed, New York University's Marion Nestle, Ph.D., who's written extensively on nutrition, said the paper was difficult to judge because it has too many "untested assumptions."
"In general, tax strategies work well for single problems -- cigarettes, for example," Dr. Nestle said. But foods usually "contain complicated sets of nutrients, some good, some bad, and figuring out which ones to tax puts things on a slippery slope."