A new study says a soda tax would lead to minimal weight loss for middle-class people and have almost no health effects on the rich and poor.
The study, published Monday in the Archives of Internal Medicine, was researched partly by Jessica Todd, an economist with the U.S. Department of Agriculture.
Todd said if a tax were enacted, poor soda drinkers would find ways to cut costs by buying in bulk or during sales. Their purchasing would also shift toward cheaper generic sodas or high-calorie juices.
“A tax might actually shift the consumption, not necessarily completely away from a caloric beverage, but maybe into a lower-priced version,” Todd said.
According to a co-author of the study, Chen Zhen, a research economist at RTI International in North Carolina, lower-income consumers already buy more cheaper store-brand sodas, which the study found to have more calories than national brands. That means that with a percentage tax, the additional tax burden for the higher-calorie generics would be smaller than for national brands.
“The effect of tax on retail price for lower income households is also smaller,” Zhen said.
Purchasing patterns of well-off consumers would be largely unchanged by the tax, the study said. But a 20 percent tax on sugar-sweetened beverages would lead to an average weight loss of three-quarters of a pound per person for the middle class.
Gary Foster, director for the Center for Obesity Research and Education at Temple University, said in the fight against obesity, every little bit counts.
“We could look at this and say, look, it’s a pound, this model says it’s mainly for the middle class, big deal,” Foster said. “That’s 10 pounds over 10 years, that’s a very big deal.”
Foster testified at City Council hearings in favor of the Philadelphia soda tax that was voted down last spring.
“It’s not troubling to me if we implement policies, each of which has a small effect,” Foster said. “And it is problematic I think to look for a policy to be the solution.”
The study used information from a database that tracked household purchases for a year to predict how a tax would affect buying patterns.
Foster said the only real way to be certain of health effects of a soda tax would be to enact one. And if tax revenues were used in health campaigns, he said there would be additional health benefits.