THURSDAY, April 12, 2018 (HealthDay News) -- Philadelphia's "soda" tax seems to be getting the results city officials wanted.

New research shows that since the city began taxing sodas, energy drinks and other sweetened beverages on Jan. 1, 2017, Philadelphians are about 40 percent less likely than residents of three nearby cities to have a soda every day. They are also 64 percent less likely to slurp down an energy drink on a daily basis, the Drexel University team said.

The new tax adds 1.5 cents per ounce to the cost of sugared and diet beverages, including sodas, fruit drinks and energy drinks -- 18 cents for a 12-ounce container. The drinks have been linked to unhealthy diets and obesity.

Bottled water, which does not come with the added tax, is now a go-to thirst-quencher. Philadelphians are 58 percent more likely to drink it every day, the survey found.

The researchers say it's a step in the right direction, but it's too soon to know if the impact will last. Critics characterize the soda tax as an example of government over-reach.

And some Philadelphians are holding fast to their beverages of choice. The city's taste for sugary fruit drinks like "Snapple" or "Sunny Delight" has not diminished even though they now cost more.

But the survey of 900 Philadelphians found that their intention to buy something like a 12-ounce can of Coke or Diet Coke has plummeted. And this, say the study authors, indicates that the added cost is having an impact, even if retailers have not yet fully passed the tax along to consumers.

"The 1.5 cents per ounce tax is one of the largest beverage taxes in the U.S. so far," said lead author Yichen Zhong, a doctoral candidate at Drexel's Dornsife School of Public Health. "If the tax is fully passed on to consumers, the price for these beverages will increase by around 20 percent."

She noted that a 10 percent soda tax passed in Mexico in 2014 appears to have spurred a lasting decrease in consumption. And the $.01 per ounce tax passed in Berkeley, Calif., in 2015 also appears to have led to a long-term dip.