Diet Pepsi Class Action Says Zero Calorie Soda May Cause Weight Gain

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A class action lawsuit filed in New York federal court alleges that Diet Pepsi containing aspartame can actually lead to weight gain and the Pepsi-Cola Company has been deceiving consumers.

Lead plaintiffs Elizabeth Manuel and Vivien Grossman allege in their class action lawsuit that because Diet Pepsi is made with aspartame acesulfame-potassium and sucralose, non-calorie sweeteners, rather than sugar, consumers are tricked into thinking that the drink will help in weight loss or management.

However, research has revealed that these non-calorie sweeteners inhibit the body’s ability to burn calories and can actually stall weight loss or even lead to weight gain, the Pepsi lawsuit states.

The plaintiffs allege that they struggled with weight management for years and relied on Pepsi’s advertising that the diet drink would help because it contained no calories.

“Pepsi’s marketing Diet Pepsi as ‘diet’ is false, misleading, and unlawful,” alleges the Diet Pepsi class action lawsuit.

According to the plaintiffs, the marketing of Diet Pepsi runs afoul of New York advertising laws and is a negligent misrepresentation on the part of the Pepsi-Cola Company. It also is a breach of express and implied warranty, say the plaintiffs.

“Due to the prominent use of the term ‘diet’ in the product’s name, Diet Pepsi, consumers reasonably believe that the product will assist in weight loss, or at least healthy weight management, for example, by not causing weight gain,” the Pepsi class action lawsuit claims. 

However, say the plaintiffs, a number of studies have shown that non-calorie sweeteners like the ones used in Diet Pepsi can lead to weight gain. One, conducted by a Yale researcher, shows that the sweet taste caused by artificial sweeteners confuses the body and throws off peoples’ metabolisms.

“In sum, calories consumed in a mismatched condition, such as when a person drinks a Diet Pepsi while eating food, are not efficiently metabolized at the time of ingestion, and may therefore be processed later, or stored, which can drive weight gain and further interfere with metabolism,” the Diet Pepsi lawsuit states. “In addition, some research has shown that sweetness — whether from sugar or noncaloric, artificial sources, increases appetite, which can lead to weight gain.”

The plaintiffs seek to represent a Class of New York residents who purchased Diet Pepsi on or after Oct. 16, 2011. The plaintiffs are seeking damages as well as a court order stopping Pepsi from marketing Diet Pepsi as a diet drink.

In addition, the plaintiffs also want Pepsi to mount a corrective advertising campaign notifying the public about the effects of the non-calorie sweeteners used in Diet Pepsi.

A similar class action was recently filed against Coca-Cola alleging that Diet Coke containing artificial sweeteners can also lead to weight gain and increase the risk of metabolic disease and diabetes.

The plaintiffs are represented by Derek T. Smith and Abraham Z. Melamed of the Derek Smith Law Group PLLC, Jack Fitzgerald, Trevor M. Flynn and Melanie Persinger of The Law Office of Jack Fitzgerald PC, and Andrew Sacks and John Weston of Sacks Weston Diamond LLC.

The Diet Pepsi False Advertising Class Action Lawsuit is Manuel, et al. v. Pepsi-Cola Co., Case No. 1:17-cv-07955, in the U.S. District Court for the Southern District of New York.

UPDATE: On Jan. 19, 2018, Pepsi argued that a class action lawsuit alleging it deceives the public with “diet” drinks that cause weight gain should be dismissed because the claims are preempted by the FDA.

UPDATE 2: On March 14, 2018, the attorneys representing plaintiffs in a proposed class action lawsuit challenging Pepsi-Cola Co.’s claims that its “diet” drinks promote weight loss asked a New York federal judge to keep the Diet Pepsi class action lawsuit alive.

UPDATE 3: On Aug. 3, 2018, plaintiffs seeking to represent a Class of Diet Pepsi buyers asked the 2nd U.S. Circuit Court of Appeals to revive a class action lawsuit alleging Pepsi-Cola Co. misrepresents its “diet” drinks as assisting with weight loss or healthy weight management.