Raising the price of sugary soft drinks will likely prompt thirsty consumers to seek out cheaper, healthier beverages, U.S. researchers said on Thursday.
They said raising the price of a can of soda by 35 percent cut soft drink sales in a hospital cafeteria by 26 percent, offering some evidence that adding a tax to soda pop may prod consumers into making better choices.
Obesity adds an estimated $147 billion a year in costs to the U.S. health care system and several states, including New York and California, have weighed a tax on sweetened soft drinks to defray the cost of obesity-related diseases.
"Obesity is at epidemic levels. It's an incredibly difficult and complicated problem," said Dr. Jason Block of Harvard University in Boston, whose study appears in the American Journal of Public Health.
He said soft drinks have been increasingly recognized as a major contributor to the country's growing obesity epidemic.
First Lady Michelle Obama last month unveiled a 70-point plan to reduce childhood obesity which called for an analysis of the impact of local sales taxes on consumption of less healthy foods.
Too much sugar not only makes people fatter, but is also a key culprit in diabetes, heart disease and stroke, according to the American Heart Association.
"Regular soft drinks make up about seven percent of all calories consumed in the United States," Block said in a telephone interview, adding that they are a "major driver" of obesity in the United States.
For the study, Block and colleagues raised the price of a can of soda by 45 cents, or 35 percent, in the cafeteria at the Harvard-affiliated Brigham and Women's Hospital in Boston and then measured the effect on sales.
The price increase applied to sugary soft drinks, which they defined as carbonated beverages with calories.
"What we found is that a price increase of 35 percent on regular soda led to a 26 percent decline in regular soda sales," Block said.
Instead of reaching for an energy drink or fruit juice, people tended to increase their consumption of diet drinks or coffee during the study period, he said.
The team compared the effect of a price increase to an educational campaign, in which the team posted signs and information about weight loss and the need to cut back on sweetened beverages.
This appeared to have no effect on buying habits of regular soda, Block said.
He said the study suggests a price increase should be part of the conversation policymakers have among themselves as they weigh options to address obesity in the United States.
"There are a number of proposals out there to levy taxes on soda. I think it's an important discussion. We see from this study there is some evidence that it could work to reduce consumption rates," Block said.
The American Beverage Association, a trade group whose members include Coca-Cola Co, Pepsico Inc, and Dr. Pepper Snapple Group, strongly opposes such taxes and says sugar-sweetened drinks are not a unique risk factor for obesity or heart disease.