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How restricting soda size makes you want to drink more

Teresa Tanoos's picture
Study shows restricting soda size makes you want to buy more

After all the controversy surrounding a proposed ban on large sugary sodas by New York City Mayor Michael Bloomberg, a new study shows that restricting the serving size of sugary drinks actually makes Americans buy more of them to compensate.

“The motivation for this study was inspired by the proposed regulations to restrict soda sizes,” said Brent M. Wilson, a doctoral student in the University of California at San Diego psychology department and lead author of the study, which was published Wednesday in the Public Library of Science (PLOS).

Although New York City passed a measure restricting the sale of sugary drinks larger than 16 ounces in an effort to wage war on the rise of obesity in America, Manhattan Supreme Court Justice, Milton Tingling, dismissed the rule as “arbitrary and capricious”. Tingling’s ruling against the ban was a victory for the soda companies and business groups that took the city to court.

The ban on large sugary sodas would have prevented restaurants, movie theaters, pushcarts and sports arenas from selling sugary drinks any larger than 16 ounces.

Just a month after the ban was tossed out of court the day before it would have gone into effect, the results of the new study came out, concluding that limiting larger servings of sugary drinks actually made consumers want to buy even more.

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The study, conducted by the University of California at San Diego, involved 100 students who were tested to see how restricting the serving size of sugary drinks affected their soda consumption. Researchers offered the participants three different menus: 1) one with 16-, 24- or 32- drinks; 2) a second with a 16 oz. drink or bundles of two 12-ounce drinks; and 3) a third with only individual 16 oz. drinks.

When the study participants chose from the menus, which was similar to placing an order at a fast-food restaurant, they purchased significantly more ounces of soda from the menu that offered bundles than with varying-sized drinks. As a result, total business revenues were also 65 percent higher when menus offered bundles of drinks instead of selling small-sized drinks only.

“Our research shows the New York City ban on large-sized drinks may have unintended consequences,” said Wilson. “Sugary drinks are a major source of business revenue, and businesses will adjust their menus in order to maximize profits.”

Indeed, the new study found that businesses had an average revenue of $1.69 when they offered drink bundles, but they only had an average revenue of $1.02 when 16 ounce drink sizes were offered. These results reveal that businesses should earn significantly more revenue when bundles are offered compared to just small drink sizes alone. Therefore, restaurants have a strong incentive to convert their original-sized drinks into bundles so they do not lose a major source of revenue.

So even though Mayor Bloomberg may have meant well with his proposed ban on limiting consumption of sugary sodas, when it comes to legislating soda consumption, you can’t expect the food and beverage industry to easily swallow it – even if it’s good for our health.

“I discourage anyone from drinking 32 ounces of soda, but the issue is: what can we legislate?” said Keith Ayoob, director of the nutrition clinic at the Children’s Evaluation and Rehabilitation Center at New York’s Albert Einstein College of Medicine. “Bloomberg’s intention was good, but people still want to have choices and the freedom to make wrong ones. It’s a sad commentary on our society that they want to legislate what people eat.”

SOURCE: Public Library of Science (PLOS), Regulating the Way to Obesity: Unintended Consequences of Limiting Sugary Drink Sizes (research article published April 10, 2013)