Regarding Sarah Kliff’s Jan. 11 Wonkblog excerpt, “An excise tax the U.S. could swallow”:

A lot of the data circulating recently on the effectiveness of a national soda tax is tied up in faulty assumptions. Ms. Kliff cited a recent study that claims a 1-cent-per-ounce tax on sugary beverages would reduce obesity rates and create a slew of health benefits for society. However, there is good evidence that while soda taxes would likely reduce soda consumption, consumers are liable to add calories elsewhere.

A 2010 study by Yale economist Jason M. Fletcher found that when adolescents stop drinking sugary beverages because of tax increases, they add exactly the same amount of calories from other food or beverages.

The study Ms. Kliff cited even acknowledged this problem, although it was not mentioned in the article. According to the study, “The greatest uncertainty in our analysis is the extent to which a reduction in calories from sugar-sweetened beverages leads to a compensatory increase in calories from food or beverages that are not taxed.”

Heavy-handed tax measures are unlikely to solve the obesity epidemic. If Americans can’t be trusted to control something as personal as our diet, what can we be trusted with?

Scott W. Drenkard, Washington

The writer is an analyst at the Tax Foundation.