In a previous post, I discussed some proposed taxes on soda and other sugary drinks and argued that the debate over the soda tax is expected to become more heated over the next few months. A new article published in Health Affairs this month provides some evidence regarding the effectiveness of soda taxes in reducing consumption and obesity among children.

Soda and other sugary drinks include carbonated soft drinks, or soda, and other sugar-sweetened beverages such as fruit punch, sweetened tea, and sports drinks. Studies have shown that these types of drinks are price sensitive: for example, a 10% increase in price leads to an 8% reduction in consumption on average. However, the effects of price increases on reduced weight, especially among school children, are unclear.

The study used data from a 2004 survey of about 7,300 fifth-graders. The researchers measured the children’s Body Mass Index (BMI) over time and collected information about how often the kids said they drank soda and sports drinks. They also reviewed taxes on carbonated drinks that were in effect at the time.

In the study, children were asked, "During the past seven days, how many times did you drink soda, sports drinks, not 100 percent juice?" They reported a mean consumption of more than six drinks per week. The findings of the study suggest that small taxes on soda (around 4%) do not have any effects on consumption and obesity among children.

However, some subgroups of at-risk children, such as children who are already overweight, come from low-income families and were more sensitive than others to soda taxes, especially when soda is available at school. For example, children who drank about seven cans of soda a week on average drank one less can because of the taxes.

The authors of the study argue that "we should not expect noticeable behavior or weight changes for children in the general population. A greater impact of these small taxes could come from the dedication of the revenues they generate to other obesity prevention efforts rather than through their direct impact on children's consumption of soda."

However, with the obesity epidemic reaching new levels and states struggling to balance budgets, some states are considering much larger taxes. For example, New York state is considering an 18% soda tax. A lot of experts disagree that the focus should be on taxes and suggest that balancing diet and exercise should be the main focus.