Starbucks has been sued in the U.S. District Court for the Western District of Washington by three consumers who allege the coffee chain falsely marketed eight protein beverages as sugar-free even though they contain lactose, a naturally occurring milk sugar. The proposed class action says venti servings contain 13 to 21 grams of sugar, while federal law bars describing a beverage as sugar-free if it contains more than 0.5 grams of sugar per 12-ounce serving. The consumers also allege Starbucks failed to provide federally required disclaimers stating that the drinks are not low-calorie food or intended for weight control. The complaint seeks unspecified damages under false-advertising and state consumer-protection laws. Starbucks, based in Seattle, had no immediate comment on Monday, and the consumers' lawyer did not immediately respond. The beverages launched in September 2025 as part of Starbucks' updated Back to Starbucks menu. The case comes amid dozens of recent lawsuits over sugar-free or zero-sugar claims involving products containing allulose, a sugar substitute.