Are Frappuccinos a sugary health risk? San Francisco apparently thinks so. The city’s controversial measure to require warning labels on billboards advertising soda would also target the Starbucks specialty, officials say.

The city’s board of supervisors tentatively approved the labels last week, aiming to alert consumers about the health dangers of sugary drinks. Billboards and posted advertising in San Francisco will include this message: “WARNING: Drinking beverages with added sugar(s) contributes to obesity, diabetes and tooth decay.”

The law draws Starbucks and its signature frozen coffee shake into a battle between local politicians and soda companies, which say they’re being unfairly targeted while high-calorie foods such as doughnuts get a pass. The measure would cover advertising for 93 Starbucks stores in San Francisco, potentially forcing the chain to tweak its signs and promotions.

The company is reviewing the ordinance “to evaluate the impact,” said Sanja Gould, a spokeswoman for Seattle-based Starbucks.

A standard 12-ounce Frappuccino, generally made with coffee, ice, milk and sugary flavored syrup, has more calories than a 140-calorie can of Coca-Cola. Even versions with nonfat milk and no whipped cream typically pass that threshold, according to Starbucks’s Web site. (A new summertime Frappuccino product, the “mini,” has 110 to 120 calories, depending on the type of milk used, according to the Web site.)

A standard 12-ounce Frappuccino has more calories than a can of Coca-Cola. (Timothy A. Clary/Agence France-Presse via Getty Images)

While the new rules exempt some coffee drinks, that exception doesn’t apply to blender beverages such as Frappuccinos, according to Jeff Cretan, legislative aide to the measure’s sponsor, Supervisor Scott Wiener.

Companion ordinances also would prohibit sugary-beverage ads on city-owned property, and the government would no longer buy sweetened beverages. A second and final vote was set for June 16, after which the measure would go to the mayor.

“These drinks are making people sick,” Wiener said in a statement, “and we need to make that clear to the public.”

The decision to approve the measures came after San Francisco voters in November rejected a ballot measure to impose a tax on sugary drinks. Voters in nearby Berkeley, meanwhile, approved a 1-cent-per-ounce tax on soda and other sugary drinks.

CalBev, the trade group representing the nonalcoholic beverage industry in the state, has called the San Francisco measure unfair.

“San Francisco’s board of supervisors chose the politically expedient route of scapegoating sweetened beverages instead of finding genuine and comprehensive solutions to the complex issues of obesity and diabetes,” said CalBev Executive Director Bob Achermann. “Singling out one industry, and one type of product, does nothing to educate people.”

— Bloomberg News