(CNN) -- New York City officials are proposing banning the sale of large-size sodas and other sugary beverages at restaurants and food carts.
"More than half of NYC adults (58%) are overweight or obese," Mayor Michael Bloomberg tweeted Thursday. "We're doing something about it."
The ban would outlaw such drinks larger than 16 ounces at restaurants, food carts and any other establishments that receive letter grades for food service. It would not apply to grocery stores.
Critics -- including McDonald's and Coca-Cola, which stand to be hurt by the proposal -- quickly assailed it as "misguided" and "arbitrary."
The New York City Department of Health will submit the measure to the Board of Health on June 12. There will then be a three-month comment period before the board votes on the proposal, officials said.
"If approved, the city's proposal would take effect six months after Board of Health approval and would be enforced by the city's regular restaurant inspection team," a statement from Bloomberg's office said. "Restaurant owners will have nine months from the adoption of the proposal until they face fines."
Fines will then be $200, the statement said.
Speaking by satellite to the All Things D technology event in California -- a previously scheduled appearance -- Bloomberg said, "This is something we think we have the legal authority to do. We¹re not taking away anybody's right to do something; we're simply making it different for them in how they do it." He said he hoped the move will help lead to different behaviors.
The city spends $4 billion a year on medical care for overweight people, he said.
The statement from his office cited health problems facing the city, including an increase in obesity. "The single largest driver of these alarming increases in obesity is sugary drinks, which have grown in size," the statement said.
It was not immediately clear what that assertion was based on.
While the consumption of sugary drinks contributes to obesity, the Centers for Disease Control and Prevention does not name a single largest cause nationally.
In a report this month, the nonprofit Institute of Medicine said, despite the "difficulty of quantifying relative contributions to the obesity epidemic, researchers have found strong associations between intake of sugar-sweetened beverages and weight gain. Although the exact mechanisms of how sugar-sweetened beverages contribute to obesity are not fully known, their link to obesity is stronger than that observed for any other food or beverage."
The New York City Health Department commissioner, Dr. Tom Farley, tweeted, "Big sugary drinks are major contributor to obesity epidemic. We're proposing to cap them at 16 oz. in restaurants."
"There they go again," Stefan Friedman, a spokesman for the New York City Beverage Association, said in a statement Thursday. "The New York City Health Department's unhealthy obsession with attacking soft drinks is again pushing them over the top. The city is not going to address the obesity issue by attacking soda because soda is not driving the obesity rates."
McDonald's restaurants issued a statement saying, "Public health issues cannot be effectively addressed through a narrowly focused and misguided ban. This is a complex topic, and one that requires a more collaborative and comprehensive approach."
A statement from the Coca-Cola company said the "people of New York City are much smarter than the New York City Health Department believes. ... New Yorkers expect and deserve better than this. They can make their own choices about the beverages they purchase. We hope New Yorkers loudly voice their disapproval about this arbitrary mandate."
But Center for Science in the Public Interest spokesman Jeff Cronin told CNN that his group considers the decision the "boldest move in the country" and "not the first time that Mayor (Michael) Bloomberg has led the charge."
"In the same way New York City generated momentum for calorie labeling and for getting rid of artificial trans fat, we hope this move today will start a national movement to ratchet down out of control soda serving sizes," Cronin said.
Broad public health initiatives have become a hallmark of Bloomberg's administration. Under the mayor, the city has banned trans fats from restaurants, smoking from parks, and has placed graphic ads targeting junk food and tobacco in public transit.
The CDC says that "many people don't realize just how many calories beverages can contribute to their daily intake."
The CDC's National Center for Health Statistics, in a brief last August, said sugar drinks "have been linked to poor diet quality, weight gain, obesity, and, in adults, type 2 diabetes."
The American Heart Association has recommended a consumption goal of no more than 450 kilocalories of sugar-sweetened beverages -- fewer than three 12-ounce cans of carbonated cola -- per week, the report says.
But Friedman, in his statement, said that "as obesity continues to rise, CDC data shows that calories from sugar-sweetened beverages are a small and declining part of the American diet."
Beverage Digest, which tracks sales, reported that in 2011, sales of carbonated soft drinks dropped by 1%, a steeper decline than the year before. Total sales of carbonated soft drinks are down to the level they were in 1996, the report said.
Per capita consumption is at its lowest since 1987, the report said.
But the CDC notes that the consumption of sugar drinks -- including non-carbonated beverages -- is higher than it was 30 years ago. And part of the key to cutting calories is "to think about what you drink," it says.
That includes watching calories in coffee drinks and smoothies, the CDC says. Just over half -- 52% -- of calories from sugar drinks are consumed at home, the CDC brief said.
CNN's Ronni Berke, Mark Norman, and Mary Snow contributed to this report.