But the sodamakers’ interests are “in complete conflict with public health needs,” said Kelly Brownell, a Yale professor who is a proponent of soda taxes and restrictions.

That’s because drinkmakers and retailers reap big profits from giant drinks, Brownell added. For just a few pennies of extra product, soda companies can sell jumbo drinks for a dollar or two more than smaller sizes.

“That’s why you have to regulate,” he said.

Bloomberg’s proposal swims against two federal policies that public health advocates say encourage soda drinking:

●Farm subsidies that push down the price of high-fructose corn syrup add about $100 million a year to the bottom line of sodamakers, according to a 2009 analysis from Tufts University researchers. Those subsidies make soda cheaper.

●The 42 million Americans receiving federal food stamps use those benefits to buy $4 billion of soda every year, according to the Center for Science in the Public Interest.