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On Thursday the New York City Health Department became the first in the nation to ban the sale of sugared beverages larger than 16 oz. at restaurants, mobile food carts, sports arenas and movie theaters.

It’s a bold experiment in the anti-obesity campaign, and while it’s widely supported by health professionals, it’s not popular with food retailers or most city residents.

The ban would prevent retailers who sell prepared food from also dispensing sugared beverages, including sodas and sweetened tea, in cups or containers larger than 16 oz. That’s smaller than your standard single-serve soda (typically 20 oz.), which you’ll no longer find at fast-food restaurants or cafeterias. Grocery stores and convenience stores, including 7-Eleven, which sells the jumbo-sized Big Gulp, would be exempt from the law, however. And the ban would not apply to fruit juices, alcoholic beverages, diet sodas or dairy-based drinks like milkshakes.

The ban on large drinks was championed by New York City Mayor Michael Bloomberg, who has a reputation for taking aggressive steps to improve city residents’ health. Often criticized for creating a nanny state, Bloomberg has been at the forefront of finding innovative, if controversial ways of nudging people to make healthier choices. Since he took office more than a decade ago, New York has become the first city to require chain restaurants to post calorie counts on their menus (the move prompted a federal law that compelled all fast food retailers in the nation to do the same) and to ban trans fats from restaurant foods. Bloomberg also banned public smoking from most corners of the city and more recently pushed hospitals to keep baby formula locked up in order to encourage breast-feeding in new moms.

(MORE: The New York City Soda Ban, and a Brief History of Bloomberg’s Nudges)

With at least two-thirds of American adults now considered overweight or obese — including more than half of New York City adults and nearly 40% of the city’s public elementary and middle school students — fighting obesity is one of the mayor’s signature causes, and sugary drinks a longtime target. In 2010, he proposed barring recipients of food stamps from using their benefits to purchase sugary beverages, a policy the federal government opposed. Last spring, he went after Big Soda again, with the proposal to ban super-sized drinks, and this time the measure was approved by the city’s health board by a vote of eight to zero.

One member of the board, Dr. Sixto Caro, abstained, noting, “I am still skeptical. This is not comprehensive enough,” the Associated Press reported.

That’s why some health officials, as well as the restaurant and beverage industry, are critical of the ban. Why single out sugared sodas, they ask; obesity has many causes and contributors, not just what people drink. And if sugared beverages are being targeted, why not take stronger measures against other sources of sugar, such as candy and other sweets? Pointing out that the average New Yorker goes to the movies just four times a year and buys concessions only twice, Sun Dee Larson, a spokeswoman for the AMC Theaters chain told the AP, “We firmly believe the choices made during the other 363 days have a much greater impact on public health.”

But the city’s health board members remain convinced that banning mega-sized drinks would be an important step toward helping consumers not only to drink fewer calories, but also hopefully to make healthier changes to their diet more broadly.

They also noted that evidence clearly shows that sugary drinks contribute to the obesity epidemic: the board reviewed data showing that sugared drinks make up 43% of the added sugar in the average American diet. Further, a 20-oz. serving of Coke contains 240 calories, compared with 200 calories in a 16-oz. size; for people who drink a soda a day, that adds up to an extra 14,600 calories a year, or about 70 Hershey chocolate bars, the AP reported. That could account for an added 4 lbs. of weight gain a year.

(MORE: From the NYC Soda Ban Hearing: The Best Arguments For and Against)

The board members said they had listen carefully to the three months of feedback from the public, when people were invited to comment on the proposed ruling. The health department says it received 32,000 comments in support of the ban and 6,000 against it. A recent poll by the New York Times, however, found that the majority of New Yorkers in every borough were against it.

Among those critical of the measure is New Yorkers for Beverage Choices, a coalition of individuals, companies and other groups that says it has collected more than 250,000 signatures from New Yorkers who feel that the new policy unfairly impinges on their right to choose what they drink. Restaurateurs and retailers, including Coca-Cola, PepsiCo and McDonald’s, are also upset over what they see as a discriminatory policy that could hurt certain businesses while rewarding others. In a statement posted on its website, the group said it would continue to challenge the ruling, including taking their concerns to court. “The fix was in from the beginning, and the Mayor’s handpicked board followed their orders by passing this discriminatory ban; but it has not passed with the support of New Yorkers,” Liz Berman, the coalition’s chairwoman, said in the statement. “We are smart enough to make our own decisions about what to eat and drink.”

Mayor Bloomberg has noted that the ban doesn’t prevent people from purchasing multiple 16-oz. sodas if they wish, but health officials hope that the inconvenience of doing so will eventually curb consumption of sugared drinks.

If legally challenged, the ban, which is expected to go into effect next March, could be delayed. Once it takes effect, the city will allow a grace period of several months during which it will let retailers know when they’re not in compliance. After that, the city will fine businesses $200 for violations.

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.