by Rebecca Quimby
April 26, 2010

U.S. children, on average, get 10 percent of their daily calories from sugar-sweetened drinks. (Gulp!) Sugar consumption has long been linked with childhood obesity. In 2006, researchers at the Harvard University School of Public Health released two reports. The first, Sugar-Sweetened Beverages and Children’s Health, reviewed trends in sugar-sweetened beverage consumption among U.S. children and the scientific evidence about the effect of such consumption on their health. And the second, Policies Affecting Access to Sugar-Sweetened Beverages and Schools: A Legal and Regulatory Review investigated policies in all 50 states. As part of a nationwide effort to reduce consumption and combat childhood obesity, several states have levied taxes on soda, and others may soon follow suit. Pay more. Drink (eat, smoke) less. That’s the theory behind sin taxes. But do they work? Do they affect children as well as adults? Two studies found conflicting results.

The first, published in the Archives of Internal Medicine, examined the use of taxes as a means for promoting healthier eating. More than 5,000 people participated in the study conducted over a 20 year period. Researchers recorded food intake, height, weight, and blood sugar levels, and compared the data with food costs during the same time period. As the cost of unhealthy foods increased, consumption of those foods decreased. In other words, when junk food was more costly, people ate less of it. A $1 increase in the cost of a soda was associated with a lower daily intake of calories, lower body weight, and better blood sugar levels. Similar results were seen with a $1 increase in the cost of a pizza. But before you cast your ballot for higher taxes on the “Pause that refreshes,” consider the results of the following study.

Published in the journal Health Affairs, researchers concluded that the current sales tax on soda (around 4 percent) did not reduce consumption or childhood obesity.

Research
With funding from The National Institute of Child Health and Human Development, the National Heart, Lung, and Blood Institute, and the Robert Wood Johnson Foundation, a group of researchers led by Roland Sturm, an economist at the RAND Corporation, examined whether a small tax changed the consumption of soda and/or weight gain of children. The study authors used individual data on more than 7,000 children from a 2004 national study. They analyzed body mass index (BMI) and total weekly consumption of sodas, sports drinks, and other sugary drinks (like non-100% juice drinks) and considered soda purchases at school. They compared this with state soda taxes from the same time period.

The researchers also took into account race and ethnicity, family income, mothers’ education levels, hours of kids’ physical activity compared with hours in front of the television, and the amount of parent-child interaction.

Results
The authors found that existing taxes on soda, generally around 4 percent in grocery stores, did not substantially affect the overall levels of soda consumption and therefore did not affect childhood obesity rates.

A look at the breakdown of soda consumption:

• The children consumed on average 6-plus sodas per week
• 15 percent of the children logged zero consumption of soda
• 25 percent consumed soda daily
• 10 percent consumed two or more drinks per day
• And 20 percent of all soda drinkers purchased an average of three sodas per week at school

The researchers did find that subgroups of at-risk children—those who are already overweight (at or above the 85^th percentile for BMI) or at risk for obesity (at or above the 95^th percentile for BMI) or who come from low-income families may be more sensitive to soda taxes, especially when soda is available at school. One reason? When tax rates increase, the price of soda in school cafeterias and vending machines round up to higher price points.

Overall, the study results suggest that small soda taxes are unlikely to have any significant effect on soda consumption or obesity among U.S. children. The study concludes that while many states will attempt to control obesity by reducing the consumption of sugary drinks and other junk food with even a small sales tax, the proposed taxes need to be much higher than the existing sales tax—closer to 18 percent, a figure that was considered in New York City just last year—to have any substantial effect.

Recommendations
It is not surprising that the study finds soda consumption to be a small part of a bigger problem. Unhealthy behaviors—poor nutrition, too much television, too little physical activity—are all contributors to childhood obesity.

Healthy behaviors start at home. A study, published in Pediatrics, shows that preschool-aged children have a 40 percent lower risk of obesity when they eat dinner as a family, view less television, and get adequate sleep. So don’t wait for a state-regulated sales tax on sodas to encourage healthy habits in your children. Instead, regulate the hours your children spend in front of the television and computer, encourage physical activity, and nix the sugary snacks, which can become a lifelong habit.