To the surprise of few, the Board of Health in New York City has passed a rule that will ban the sale of large soft drinks and other sugary drinks at restaurants, concession stands, and other eateries.

The new regulation means that fast-food restaurants, movie theatres, workplace cafeterias, and most other places selling prepared food will no longer be able to sell sweetened drinks that are larger than 475 millilitres (16 ounces).

The ban doesn't apply to lower-calorie drinks, such as water or diet soda, or to alcoholic beverages. Nor does it apply to drinks that are more than half milk or 70 per cent juice. The ban also doesn’t cover beverages sold in supermarkets or convenience stores.

City restaurant inspectors will be in charge of enforcing the new rules, which should go into effect in March, 2013. Anyone caught violating the ban could face a US$200 fine.

The ban was proposed in the spring by Mayor Michael Bloomberg and approved by the panel of health experts after several months of review.

There had been little doubt the ban would pass, since all the members of the city’s Board of Health were appointed by Bloomberg.

But many, including the restaurant and beverage industries, have called the plan misguided, saying the role that sugary beverages play in the obesity crisis is being exaggerated. Some New Yorkers have also ridiculed the rule as another example of government intrusion.

A soft-drink industry-sponsored group called New Yorkers for Beverage Choices says it has gathered more than 250,000 signatures on petitions opposing the soda plan. It also says it’s considering a lawsuit.

Bloomberg has defended the ban, saying people would still be free to buy as many 16-ounce drinks as they liked.

"Nobody is restricting the amount of sodas you can buy or the amount of sodas you can drink," he said. "It is simply using portion control to point out to you ... how many calories you are consuming."

Advocates note that while there is only a 40-calorie difference between a 16-ounce cola and a 20-ounce (200 calories vs. 240 calories), those calories can add up. For someone who drinks even just one soft drink a day, the difference amounts to 14,600 calories a year, or enough to add about four pounds to a person's body.

David Burwick, the president of Weight Watchers North America, agrees that while the move won’t solve the obesity crisis on its own, it’s an important first step.

"We all need to take more personal responsibility for our own weight and eating habits, but it helps to remember what a healthy portion size is in a world where super-size portions have become the norm,” Burwick said earlier this month.