WASHINGTON (Reuters) - New York City's top health official shot back on Thursday at critics who have blasted the city's plan to limit the sale of oversized sugary drinks such as soda, calling beverage industry opposition ridiculous.

The proposed ban, which caps most sugar-sweetened beverages at 16 ounces (half a liter) and carries a $200 fine for vendors that do not comply, met immediate backlash from beverage companies and others who argue it is government overreach, but was lauded by public health experts.

"It's not saying 'no' to people. It's saying, 'Are you sure? Do you really want that?'" Thomas Farley, New York City's health commissioner, said. "It's sending people a message while giving people the freedom to drink as much as they want."

Speaking at a conference in Washington aimed at reducing the consumption of sugary beverages, Farley said drink makers were following the same playbook as tobacco companies that push back against government action aimed at protecting consumers from harmful products.

Coca-Cola Co and McDonald's Corp along with beverage industry groups have said consumers should be able to make their own drink choices and that sodas are not to blame for the nation's soaring obesity rates.

The industry has launched a wave of ads in response to New York's plan, which Mayor Michael Bloomberg announced last week.

Farley said sugary drink consumption may just be part of the U.S. obesity epidemic but that such products were the largest single source of sugar in the diet and had a major impact on health. Reducing obesity by just 10 percent in New York City would save about 500 lives a year, he added.

"It's ridiculous to say we shouldn't try something that's only going to solve a portion of the problem," he said at the event, which was sponsored by the Center for Science in the Public Interest, a group that has long advocated against junk food.

American Beverage Association spokeswoman Karen Hanretty, in a statement, defended the industry's response and said there was little support for Bloomberg's proposal. Many people think the plan "has gone too far with a proposal that will do nothing to reduce the serious problem of obesity in America," she said.

COULD TAKE EFFECT NEXT YEAR

The city's cup-size ban will be submitted on Tuesday to the New York City Board of Health, which will vote on it after a three-month comment period. If approved by the board, the ban would take effect early next year.

The beverage industry is expected to spend large amounts of money to fight it. Legal analysts have said drink makers face an uphill battle in the courts if they pursue legal challenges to block the effort.

"There are so many examples where states impose standards on consumer products sold within their borders," Michelle Mello, a Harvard University professor of law and public health, said on Monday. "It seems hard to believe that this would be singled out as unreasonable by a court."

Public health experts have embraced Bloomberg's plan and see it as an approach that could be applied in communities across the country.

Farley and other health advocates at the conference said they were confident that people over time would embrace smaller cup sizes as the right thing to do just as they eventually came around to bans on smoking in public places.

"If we can do that for .... tobacco, we can certainly do that for obesity as well," Farley said.

Kelly Brownell, director of the Rudd Center for Food Policy and Obesity at Yale University, said targeting sugar-sweetened beverages made sense because they offered empty calories with no nutritional value.

Another U.S. mayor, Michael Nutter of Philadelphia, told the conference he had seen some progress from drink makers selling smaller sizes and low-calorie or no-calorie products, but they were not owning up so far to their role in the nation's weight struggle.

"The industry needs to at least acknowledge that they are part of the problem," he said.