Does A Soda Tax Reduce Obesity?

See Slim Odds: Empirical studies provide little evidence that soda taxes would shrink Americans’ waistlines by Jonathan Klick (University of Pennsylvania School of Law)and Eric A. Helland (Claremont McKenna College). Excerpt:

"The most sophisticated research in this field using actual state soda taxes to identify the effect of such taxes on obesity is done by Jason Fletcher, an economist at the Yale School for Public Health, and co-authors. Fletcher et al. have examined the effects of taxes on consumption and ultimate weight effects for both adults and children. During the period 1989–2006, an average of 21 states taxed soda, with an average rate ranging from 4.1 to 5.1 percent. In a research paper published in the Journal of Public Economics, Fletcher et al. used panel data methods to account for baseline differences across states (e.g., people are generally fatter in Pennsylvania than in Utah) as well as underlying national trends. Controlling for those factors, the researchers found that a one percent increase in the soda tax leads to a five percent reduction in calories consumed from sodas among young people age 3–18. While this result is statistically significant, Fletcher et al. call the reduction “modest” because sodas are only a small part of the average person’s total caloric intake.

Interestingly, the researchers did not find that the children substituted toward diet sodas or water, as is generally assumed by proponents of sugarsweetened soda taxes. Instead, they found that the 6-calorie reduction in soda consumption is accompanied by an 8-calorie increase in milk consumption and a 2-calorie increase in juice and juice drink consumption. That is, any obesity-related benefit of decreased soda consumption that comes from a soda tax is, on average, more than offset by increased caloric consumption from other beverages. As expected, given these results, when the researchers directly examined data on the body mass index of the children in their dataset, they found no statistically significant effect of soda taxes on body weight or the likelihood of being obese or overweight. In fact, although the results are not significant, they found a positive relationship between increases in soda taxes and these metrics."