Mayor Michael Bloomberg made headlines when he proposed a ban on selling sodas larger than 16 ounces at New York City eateries.
Under the law, restaurants, fast food chains, delis, sports venues, movie theaters and street vendors would not be allowed to sell bottles and cups of sugar-sweetened beverages that exceeded the size limit. Refills, however, and the option to purchase additional 16-ounce beverages are permitted under the law.
A new study suggests this type of law may backfire and actually cause people to purchase more sugary beverages.
"Our research shows the New York City ban on large-sized drinks may have unintended consequences that policy makers need to consider," study author Brent M. Wilson, a graduate student in the department of psychology at UC San Diego, said in a press release.
The city's soda ban wasin March 2013, before New York Supreme Court Judge Milton Tingling ruled the day before its implementation that the city may not enforce the new regulation. Tingling called the law "arbitrary," because of loopholes in the regulations, such as exemptions for milk-based beverages sold at restaurants and sugary drinks sold at grocery and convenience stores.
The researchers wanted to see anyway whether this type of ban would have its intended effects.
For the study, published April 10 in PLoS One, Wilson and fellow researchers offered 100 participants three kinds of menus. One "unregulated" menu offered drinks in 16 ($1.59), 24 ($1.79) or 32-ounce sizes ($1.99), one menu offered only 16-ounce drinks (also for $1.59) for sale and the third offered either one 16-ounce soda ($1.59) or bundles of two 12-ounce ($1.79) or 16-ounce ($1.99) sodas.
The menus were presented on paper that had drawings of cups, a popcorn container and slices of pizza . Participants were randomized to purchase the items as if they were at a fast food restaurant, movie theater or stadium to mimic establishments where the New York City ban would take place.
Participants bought significantly more soda from the menu with bundles of 12 ounce and 16 ounce drinks than they did when offered individual sodas of different sizes.
The researchers also determined based on these choices, that businesses could make more money bundling drinks than only offering one small size. Bundled drinks also outsold the unregulated menu with multiple sizes, which suggests this type of soda ban could make businesses more money.
"Sugary drinks are a major source of business revenue, and businesses will adjust their menus in order to maximize profits," said Wilson.
The researchers wrote that the study had limitations, including that it didn't actually measure how much soda participants consumed, only what they bought.
Barbara Jean Rolls, chair of nutritional studies at Penn State University, also pointed out to HealthDay that the study lacked the real-world component because it did not take place in an actual restaurant, and participants were simply told the setting they were in.
However, one expert thought there was truth to this effect.
"Most people getting ready to buy soda will go for the regular size," David Just, a professor of behavioral economics at Cornell University in Ithaca, N.Y., told the Los Angeles Times. He was not involved in the research.
However, for those who want a large soda and are prevented from buying one, "they're going to display what we call reactance -- a rebelliousness, a determination to circumvent this policy, an attitude of 'I'll show them.' And the people selling the soda are all too willing to comply."