An appeals court has ruled that New York City's ban on large sodas and sugary drinks is unconstitutional.

In a unanimous opinion, the four-judge panel of the state Supreme Court Appellate Division said the city's Board of Health exceeded its legal authority and acted unconstitutionally when it tried to institute a size limit of sixteen ounces (479 ml) on sodas and sugary drinks sold at restaurants, movie theatres, sports venues and street carts.

The health board was acting too much like a legislature when it created the limit, the judges said.

While the board had the power to ban "inherently harmful" foodstuffs from being served to the public, sweetened beverages didn't fall into that category, the judges wrote. They also said the board appeared to have crafted much of the new rules based on political or economic considerations, rather than health concerns.

New York's law department promised a quick appeal.

"Today's decision is a temporary setback, and we plan to appeal this decision as we continue the fight against the obesity epidemic," Mayor Michael Bloomberg said in a statement.

Decision backs lower court ruling

The ban had been struck down by a lower court in March, hours before it was to go into effect. The court ruled that the ban was unfair and too arbitrary because it would have applied to only some sugary beverages and some places that sell them.

The ban was to apply to bottled drinks as well as fountain sodas but not to diet sodas, fruit juices, dairy-based drinks, including lattes, or alcoholic beverages. It would have also excluded drinks sold in grocery or convenience stores, which aren't subject to municipal regulation. Food establishments that didn't downsize faced a $200 US fine.

The city appealed the Supreme Court ruling.

"This measure is part of the city's multi-pronged effort to combat the growing obesity epidemic, which takes the lives of more than 5,000 New Yorkers every year, and we believe the Board of Health has the legal authority — and responsibility — to tackle its leading causes," said the city's corporation counsel, Michael A. Cardozo, said at the time.

Ban part of broader health campaign

New York's effort to cap soda portions has drawn national attention, whether from diet companies lauding it as a groundbreaking step in America's war on extra weight or from late-night TV hosts ribbing Bloomberg as a nutrition nanny.

The drinks limit follows other Bloomberg efforts to nudge New Yorkers into better diets. His administration has forced chain restaurants to post calorie counts on menus, barred artificial trans fats from restaurant fare and challenged food manufacturers to use less salt.

Bloomberg and city Health Commissioner Thomas Farley saw soft drinks as a sensible next front in a necessary fight: reining in an obesity rate that rose from 18 to 24 percent of adults in the city within a decade. Studies have tied heavy consumption of sugary drinks to weight gain, and the city had to start somewhere, the officials said.

"We have a responsibility, as human beings, to do something, to save each other. ... So while other people will wring their hands over the problem of sugary drinks, in New York City, we're doing something about it," Bloomberg said at a news conference after the measure was struck down in March.

Ban would have hurt business, critics say

Critics said the city went too far in imposing a serving size limit.

"For the first time, this agency is telling the public how much of a safe and lawful beverage it can drink," Richard Bress, a lawyer for the American Beverage Association and a coalition of other groups that challenged the regulation, told the appeals court at a hearing in June. "This is the government coercing lifestyle decisions."

Opponents also said the measure's limitations made it meaningless as a health tool but potentially devastating to businesses that would have to deny customers big sodas while neighbouring establishments could still supersize them.

The lower court judge, state Supreme Court Justice Milton Tingling, wrote in March that "the loopholes in this rule effectively defeat the stated purpose."

While the city appealed, Bloomberg has continued pushing the cause in other ways. In June, he and the mayors of 15 other cities urged congressional leaders to stop allowing food stamps to be used to buy soda and other sugary drinks, reviving an idea that had been broached for years.