The New York City Board of Health on Thursday voted 8-0 to enact Mayor Bloomberg's ban on large sodas in a broad range of venues, including restaurants and movie theatres.

Starting March 12, food businesses regulated by the city will not be able to sell many sugary drinks in containers larger than 16 ounces. Diet beverages (including diet soft drinks), unsweetened coffee and tea, juice drinks and milkshakes would not fall under the size cap. At venues with free refills, the largest cup available to customers will be 16 ounces.

Businesses that are regulated by the state and not the city -- a group that includes Big Gulp purveyor 7Eleven -- are also unconstrained by the soda size cap.

City officials and nutritionists say the cap is an important salvo in the city's fight against obesity.

"After months of misleading criticism and a barrage of advertisements from industry-sponsored 'grass-roots' groups, it is crucial we all remember how serious the obesity crisis is," New York City Health Commissioner Thomas Farley said in an opinion piece for the New York Daily News Thursday.

More than half of adults and 40% of children in New York City are overweight or obese, according to Farley.

Soon after Mayor Bloomberg proposed the plan in May, business groups opposed to the bill responded in force, with ad campaigns on delivery trucks and movie theatre marquees exhorting moviegoers to join their coalition, New Yorkers For Beverage Choices.

Six out of 10 New Yorkers opposed the plan, according to a recent poll by the New York Times.

The industry is hardly cowed by the health board's decision. In a video released Thursday, New Yorkers for Beverage Choices chairman Liz Berman pointed to the NYTimes poll and said that "we have to continue this fight. We have to make sure that our voices are heard."

Columbia University bioethicist John Loike is not especially in favor of the mayor's plan either; he says what might work better is applying extra taxes, as with cigarettes.

"The idea of banning foods goes against autonomy," Loike said in a phone interview. "The idea is that people should be educated."

Others feel the ban, while a step in the right direction, will play a minimal role in the battle against obesity.

"Realistically, banning sugary drinks is just one piece of the obesity puzzle," Karen Congro, director of wellness at The Brooklyn Hospital Center, said in a statement Thursday. "Many people are emotionally connected to food and don't understand what constitutes a proper portion -- even of healthy foods -- and that's why we see so much childhood obesity."

Marion Nestle, an author and nutrition professor at New York University, endorses the cap -- also citing cigarettes in her support.

"Telling people cigarettes cause cancer hardly ever got anyone to stop. But regulations did," Nestle wrote in a column for the San Francisco Chronicle in August. "Taxing cigarettes, banning advertising, setting age limits for purchases and restricting smoking in airplanes, workplaces, bars and restaurants made it easier for smokers to stop."

Food regulations also have a proven track record, Nestle said in a phone interview. The recent ban on trans fats throughout New York City restaurants has markedly reduced the levels of trans fat in New Yorkers' blood, and states with strong regulations about what kinds of foods can be served in schools have lower levels of child obesity, she says.

Research shows that people will tend to choose a default meal option, so by changing the default, the city can encourage healthier choices, she says.

Plus, Nestle says, "this isn't a ban, it's a cap." If someone really wants to drink 32 ounces of soda at the movies, "you can always order two."