Messages that convey the dangers associated with consumption of sugar-sweetened beverages (SSBs) may be the most effective means of changing attitudes toward consumption and policy preferences. However, there is a risk that this message type also stimulates reactance, a form of resistance to persuasion. A study (N = 618) using messages from the 2012 New York City anti-SSB campaign and a sample of New York City residents showed just such effects. Reactance was heightened by prior message exposure, conservative political orientation and prior consumption of SSBs. The net message effect was still persuasive overall for attitudes, but could be improved by 17% if reactance were eliminated. In contrast, the net message effect on policy preferences was counterpersuasive, due to processes other than reactance. Anti-SSB threat appeals can change attitudes toward one's own behavior in a more healthful direction, while simultaneously eroding support for more restrictive SSB policies.