By Mike Pomranz
Updated August 25, 2016
© Richard Levine / Alamy

The concept of taxing sugary beverages has caused plenty of debate between health advocates and soda companies. One of the bigger points of contention has always been whether or not so-called “soda taxes” would actually have their desired effect, a reduction in soda consumption. But now that a couple major cities – Berkeley, California, and Philadelphia, Pennsylvania – have actually enacted this kind of tax, both sides of the argument will finally have something we’ve yet to see on this subject in the US: empirical evidence.

This week, the results of an early study suggest that, indeed, taxing sugary beverages reduces their consumption – at least in the low income neighborhoods of Berkeley that the study assessed. The research -- conducted at the University of California, Berkeley and published in the American Journal of Public Health – compared interviews with local residents both before and after the city’s soda tax went into effect in March 2015, according to the Wall Street Journal. The “before” interviews took place in 2014; the “after” ones occurred between April and August of 2015.

The results show that self-reported consumption dropped 21 percent during this period, an even more eye-opening number when you take into consideration that soda consumption in similar neighborhoods in the nearby cities of San Francisco and Oakland actually rose by 4 percent over the same period. Though the study’s authors admit that other factors beyond the tax could be involved, such as increased awareness of the negative health impacts of sugary drinks, the San Francisco stat, for instance, would seem to negate that argument, since San Francisco also held a major vote on a soda tax during the same election Berkeley did – meaning that even though that legislation didn’t pass, awareness in the city still should have been high.

Also worth noting, the study shows that water consumption in Berkeley jumped 63 percent over the approximately one-year period. Meanwhile, San Francisco and Oakland only saw a 19 percent bump. Number junkies may also be interested to know the breakdown on Berkeley’s beverage consumption decrease: Regular soda consumption was down 26 percent; energy drink consumption was down 29 percent; sports drinks saw the largest decline at 36 percent; and other sweetened beverages like fruit drinks, coffee and tea dropped 13 percent.

Needless to say, the American Beverage Association, a soda industry group, questioned the study’s merits, saying, among other criticisms, that none of this really shows that public health is improving. It a valid point – but based on the results of this research, the anti-soda crowd is probably chomping at the bit for more and more of empirical evidence to keep rolling in.