New York City Mayor Michael Bloomberg is pulling out all the stops in his campaign to stop rising obesity rates. Following the city's directives to tax soft drinks, list calories on restaurant menus, and limit sodium intake, the mayor's latest "FAT-wah" proposes that food stamps cannot be used to purchase soft drinks. While his motive is pure, singling out a specific product (like soda) is not an effective way to curb excessive calorie consumption.
Sodas are the whipping boy du jour, and it is emotionally and politically easy to take on this "villain." After all, polls have shown that three-quarters of New Yorkers are in favor of "fat taxes." But let's not get confused by the facts. USDA Economic Research Service data indicates that although available calories of caloric sweeteners per capita have increased 14.6 percent since 1970, the percentage of calories contributed by sugars and sweeteners has actually declined from 18.4 percent to 17.3 percent.
The simple fact is that there are too many calories on the street regardless of the source—up 30 percent per person since 1970. This premise is not based on industry favoritism. It's supported by serious research as reported in the New England Journal of Medicine, where lead researcher Dr. Frank Sacks of the Harvard School of Public Health stated, "It's not so much whether that food is carbohydrate-rich or protein-rich. It really comes down to calories, a very simple message." So going after one product category just shifts consumption to other high-calorie products. Consideration of this "substitution effect" has been notably absent in virtually all sin tax analyses.