Tipping point, inspiration, harbinger. Those were the words that public health advocates are using to describe Philadelphia City Council's vote to advance the first big-city levy on soda.

"The arc of history is bending toward public health," said Jim O'Hara, health promotion director for the Center for Science in the Public Interest, which has been pushing for years for taxes on sugar-sweetened beverages as a way to attack epidemics of obesity and diabetes.

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