In April 2015, the US Right to Know (US RTK), a non-profit organization that reports on food industry issues on behalf of consumers, sent a letter to the Federal Trade Commission (FTC) and a citizen petition to the Food and Drug Administration (FDA) with requests to investigate diet soda manufacturers for misbranding and deceptive advertising on the grounds that the “diet” products contain artificial sweeteners that US RTK alleges actually contribute to weight gain.

The request for FTC investigation states that the soft drink companies deceptively imply that artificially sweetened beverages contribute to weight loss rather than weight gain and requests that the FTC prohibit the companies from using the term “diet” in advertising such products. US RTK argued that representing that such products are “diet” is likely to mislead reasonable consumers, and that consumers will rely on the claims to their detriment.

In the FDA citizen petition, US RTK requests that FDA 1) issue a warning letter for use of the term “diet” as being false and misleading, and 2) investigate the use of the term “diet” (and other terms implying weight loss in other artificially sweetened products) to determine if the product brand names or labels are misbranded.