In 2017, several plaintiffs began bringing lawsuits in California and New York premised on the theory that “diet” sodas — i.e., sodas sweetened with zero-calorie artificial sweeteners rather than sugar — were mislabeled because the sodas falsely suggested they would help consumers lose weight, even though aspartame and other artificial sweeteners are supposedly associated with weight gain. Courts have routinely dismissed these lawsuits on one of two grounds:

  • Some courts have concluded that this theory of deception is implausible because reasonable consumers understand the term “diet” to mean that the soda has zero calories, not that it will help them lose weight. See, e.g., Geffner v. Coca-Cola Co., 928 F.3d 198, 200 (2d Cir. 2019) (“[T]he “diet” label refers specifically to the drink’s low caloric content; it does not convey a more general weight loss promise.”); Becerra v. Coca-Cola Co., No. 17-5916, 2018 WL 1070823, at *3 (N.D. Cal. Feb. 27, 2018) (“Reasonable consumers would understand that Diet Coke merely deletes the calories usually present in regular Coke, and that the caloric reduction will lead to weight loss only as part of an overall sensible diet and exercise regimen dependent on individual metabolism.”).
  • Other courts have dismissed these lawsuits on the basis that the scientific literature cited by the plaintiffs does not support a causal relationship between zero-calorie sweeteners and weight gain. See, e.g., Excevarria v. Dr. Pepper Snapple Grp., Inc., 764 F. App’x 108, 110 (2d Cir. 2019) (affirming dismissal of lawsuit challenging labeling of Diet Dr. Pepper, as “[n]one of the studies cited . . . establish a causal relationship between aspartame and weight gain”).

The Ninth Circuit recently joined the chorus of courts that have rejected this theory of deception. In Becerra v. Dr. Pepper/Seven Up, Inc., the district court dismissed a lawsuit alleging that Diet Dr. Pepper was mislabeled as a “diet” soda, both because the plaintiff had not alleged that consumers construed the term “diet” as a representation about weight loss and because the plaintiff had not sufficiently alleged that aspartame is associated with weight gain. On December 30, 2019, the Ninth Circuit issued a published decision affirming the dismissal of this lawsuit. Becerra v. Dr. Pepper/Seven Up, Inc. --- F.3d ----, 2019 WL 7287554 (9th Cir. 2019).

The Ninth Circuit began by explaining that California’s consumer protection statutes require the plaintiff to allege that consumers are “likely to be deceived” — not simply a “mere possibility that Diet Dr. Pepper’s labeling might conceivably be misunderstood by some few consumers viewing it in an unreasonable manner.” Id. at *3. Applying this standard, the Ninth Circuit agreed that the term “diet” was not likely to mislead a reasonable consumer. In so holding, the Ninth Circuit rejected the plaintiff’s reliance on dictionary definitions of the term “diet”; even though this term may imply weight loss when used as a noun, the court explained, it clearly implied that a product was “reduced in or free from calories” when used as an adjective. Id. And while the plaintiff argued that consumers could nonetheless “misunderstand” the term “diet” to suggest weight loss benefits when used in this context, the Ninth Circuit made clear that such “unreasonable assumptions” would not give rise to a plausible claim of deception. Id. at *4. (“Just because some consumers may unreasonably interpret the term differently does not render the use of ‘diet’ in a soda’s brand name false or deceptive.”).

The Ninth Circuit also rejected the plaintiff’s remaining arguments about why consumers might interpret the term “diet” as a representation about weight loss. It held that the use of “attractive, fit models” in its advertisements did not suggest to consumers that drinking Diet Dr. Pepper would “help its consumers achieve those bodies.” Id. It also rejected the plaintiff’s reliance on American Beverage Association blog posts suggesting that consumers associate diet soft drinks with weight loss, as those blog posts “emphasize that other lifestyle changes beyond merely drinking diet soft drinks are necessary to see weight-loss results.” And it likewise rejected the plaintiff’s reliance on a survey showing that consumers expected diet soft drinks to help them lose weight or maintain their current weight: even accepting the survey’s findings at true, the Ninth Circuit nonetheless held that “a reasonable consumer would still understand ‘diet’ in this context to be a relative claim about the calorie or sugar content of the product.” Id. at *4-5. Because the survey “does not address this understanding or the equally reasonable understanding that consuming low-calorie products will impact one’s weight only to the extent that weight loss relies on consuming fewer calories overall,” the Ninth Circuit concluded that it did not support the plaintiff’s claims of deception. Id. at *5.