Starbucks sued over 'sugar-free' claims for protein beverages

By Jonathan Stempel

Oct 5 (Reuters) - Starbucks SBUX.O has been sued by consumers who said the coffee chain falsely advertised eight protein beverages as "sugar-free" because they contain lactose, a naturally occurring sugar in milk.

• According to a proposed class action filed on Friday, reasonable consumers would not expect the beverages to contain 13 to 21 grams of sugar per 20- or 24-ounce "venti" serving.

• Federal law prohibits Starbucks from using "sugar-free" to describe beverages containing more than 0.5 grams of sugar per 12-ounce serving, the complaint said.

• Consumers accused Starbucks of trying to capitalize on the desire of 75% of Americans to reduce or eliminate sugar consumption. They also said Starbucks failed to provide federally required disclaimers that the protein beverages are not low-calorie food or meant for weight control.

• Starbucks, based in Seattle, had no immediate comment on Monday. A lawyer for the consumers did not immediately respond to requests for comment. The complaint in Seattle federal court seeks unspecified damages for false advertising and violations of various state consumer protection laws.

• Food producers are regularly sued for alleged false advertising, including in dozens of recent cases challenging "sugar-free" or "zero sugar" claims for products containing a sugar substitute known as allulose.

• The eight Starbucks beverages are Sugar-Free Vanilla Protein Latte, Sugar-Free Caramel Protein Latte, Sugar-Free Vanilla Protein Matcha, Sugar-Free Caramel Protein Matcha, and equivalent versions containing ice.

• The Starbucks website says the beverages are "protein-packed" with "no added sugar," and venti servings contain between 270 and 340 calories. The company launched the beverages in September 2025 as part of its "Back to Starbucks" updated menu.