(CBS/AP) NEW YORK - Weight Watchers, Jenny Craig and other diet companies voiced their approval for New York City's proposed soda ban during a press conference featuring Mayor Michael Bloomberg and a Weight Watchers' official on Tuesday.
The announcement was the latest in a volley of statements of support for both advocates and critics of the plan, which calls for restaurants, movie theaters, sports arenas, food carts and delis to stop selling sodas and other sugary drinks in servings larger than 16 ounces.
Bloomberg and other proponents call it a sensible way to encourage people to cut calories. Opponents see it as government overreaching and question its effectiveness.
To the diet groups, it's a tool that fits with their approach to making healthy eating easier.
''Today, we live in a world where despite our best intentions, it's oftentimes very difficult on your own to make the healthy choice,'' said David Burwick, president of Weight Watchers North America. ''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.''
The proposal is set for a Sept. 13 vote at the city Board of Health, whose members are appointed by Bloomberg. If approved, it would take effect as early as March.
Bloomberg has been the leading advocate for the plan, which follows other efforts to spur New Yorkers to mind what they eat. During his 11-year tenure, the city has barred artificial trans fats from food served in restaurants and compelled chain restaurants to post calorie counts on menus.
Still, the city spends roughly $4 billion a year on weight-related health problems, the mayor says. He sees limiting the serving size of sugary drinks as a meaningful step -- but not an inflexible order -- to keep people from downing calories they might not even think about.
"Nobody is restricting the amount of sodas you can buy or the amount of sodas you can drink," he said, noting that people would be free to purchase multiple 16-ounce cups or bottles if they liked. "It is simply using portion control to point out to you ... how many calories you are consuming."
Along with Weight Watchers and Jenny Craig, the creator of the South Beach Diet, the founder of The Best Life and other diet experts expressed their support. City Hall also has released a roster of kudos from people including physicians, elected officials, chef Jamie Oliver and filmmaker Spike Lee.
Critics, too, are counting their ranks.
An opposition group called New Yorkers for Beverage Choices said it has the backing of more than 2,000 businesses and 201,000 people. A New York Times poll last month showed that six in 10 New Yorkers opposed the plan.
In July 2012, protesters gathered at City Hall in an event called "Million Big Gulp March." They argued that the government shouldn't have the right to tell them what to do or drink.
"Before, the government was instituted to protect the rights of everyone and prevent crime, and now it's cracking down the rights of everyone," NYC Liberty HQ spokesman Zach Huff told CBS News.
Opponents say the city is overstepping its authority and infringing on personal freedom. And they call the diet companies' stance inconsistent with their own emphasis on letting people make food choices, rather than absolute limits.
''Restrictions and bans will do nothing to address the very complex issue of obesity,'' New Yorkers for Beverage Choices said in a statement Tuesday. ''New Yorkers are smart enough to make their own decisions.''
Some City Council members support the proposal; others have criticized it. During a July 2012 public meeting with NYC's health board, City Councilman Daniel Halloran III called the proposal a "feel-good placebo" that hurt small businesses trying to make money.
Chris Gindlesperger, a spokesman for the American Beverage Association, argued that saying soda makers were like tobacco companies didn't make sense.
"There's no comparison," he said. "Cigarettes can kill you. ... Soft drinks are a treat to be enjoyed in moderation - they can play a role in a healthy, balanced and active lifestyle."
Regardless, it isn't scheduled to come before them for a vote.
The rule wouldn't apply to lower-calorie drinks, such as water or diet soda, nor to alcoholic beverages or drinks that are more than half milk or 70 percent juice.