A court has blocked a ban on the sale of large sugary drinks - including soda - from restaurants in New York City, a day before the law was to take effect.
Judge Milton Tingling ruled that the measure was "arbitrary and capricious", after industry groups sued the city.
The law would forbid the sale of drinks larger than 16 ounces (473ml) in food-service establishments.
Mayor Michael Bloomberg said the judge was "totally in error" and has vowed to appeal against Monday's ruling.
He has touted the ban as a way to reduce obesity. Research suggests that 58% of adults in New York are obese or overweight.
'Sigh of relief'
In his ruling, Judge Tingling wrote that loopholes in the law "effectively defeat the stated purpose".
The American Beverage Association, which is leading the fight against the ban, welcomed the decision.
"The court ruling provides a sigh of relief to New Yorkers and thousands of small businesses in New York City that would have been harmed by this arbitrary and unpopular ban," it said.
The law would apply to places serving food, ranging from pizzerias to sports stadiums and cinemas, though not at supermarkets or stores.
The measure was approved in September by the city Board of Health to come into force on 12 March, with fines of $200 (£134) not to be levied until June.
The judge ruled that the Bloomberg-appointed board had strayed into legislative territory that should belong to the elected City Council.
Mayor Bloomberg responded to the ruling by telling a news conference: "We think the judge is totally in error in the way he interpreted the law and we are very confident that we will win on appeal.
"One of the cases we will make is that people are dying every day. This is not a joke. Five thousand people die of obesity every day in America," he added.