New York Mayor Michael Bloomberg's anti-obesity campaign to ban the sale of certain sugary drinks in large servings, especially sodas, was struck down last month in state court. A proposal for a penny-per-ounce excise tax on sweetened beverages also floundered in Vermont's House of Representatives in February.

Yet Mayor Bloomberg has vowed to fight on, and the wider government war on obesity shows no sign of abating. Municipalities and states continue to target sodas. In February, a bill to levy a penny-per-ounce tax was introduced...