Plaintiff Shana Becerra filed a class action complaint against The Coca Cola Company claiming that Diet Coke actually caused weight gain instead of weight loss, allegedly constituting false advertising. Plaintiff claimed that non-nutritive sweeteners, such as aspartame found in Diet Coke, interfere with the ability to metabolize calories leading to increased weight gain, while also raising the risk of cardiovascular disease and diabetes. 

Plaintiff did not argue that Coca-Cola has made any affirmative statements or representations that Diet Coke would cause weight loss, but instead, plaintiff argued that Coca-Cola's use of the word "diet" in its Diet Coke product "inherently and necessarily implies that it will assist in weight loss."

In granting Coca Cola’s motion to dismiss, U.S. District Judge William Alsup for the Northern District of California found that the 13 studies upon which Plaintiff relied to support her claims were “equivocal” as to whether diet soda causes weight gain. In so holding, Judge Alsup noted that supermarkets do not display Diet Coke in the health food section. Judge Alsup further held that reasonable consumers would understand that any caloric savings would lead to weight loss only as part of a “sensible diet and exercise regimen.”

Judge Alsup’s decision comes one month after Coca-Cola rebranded Diet Coke by using taller, thinner cans and adding flavors such as blood orange, cherry, ginger-lime and mango.