San Francisco has launched a significant legal offensive against major food manufacturers, marking a new front in the battle over ultra-processed foods and public health.
On 2 December 2025, the San Francisco City Attorney sued nine large food manufacturers over allegations relating to ultra-processed foods, commonly referred to as UPFs.
The complaint alleges violations of California’s Unfair Competition Law and public nuisance law, targeting companies accused of engineering addictive products and concealing known public health harms.
Defendants are also accused of deliberately targeting minority and low-income communities with ultra-processed food products, a claim that could carry significant weight in court.
Ultra-processed foods have no formal legal definition, but are generally understood to contain one or more ingredients not found in an ordinary kitchen, such as modified starches, emulsifiers, and chemical preservatives.
Common examples of UPFs include chips, soda, processed meats, boxed macaroni and cheese, and some breakfast cereals, all typically engineered to be high-calorie and quickly consumed.
By framing UPFs as a source of societal harm rather than a private injury, the city shifts focus away from proving individual harm and toward demonstrating broader damage to public health.
This approach mirrors strategies used in lead paint litigation, where government plaintiffs sought abatement of a public nuisance without needing to tie liability to any one person’s injury.
The case was remanded to California state court on 23 April 2026, after federal diversity jurisdiction could not be maintained where the state was determined to be the real party in interest.
The Consumer Brands Association has criticised the suit, arguing that companies complying with federal food-safety and labelling rules should not face public nuisance liability under state law.
Legal analysts warn that if the Unfair Competition Law and public nuisance theories survive dispositive motions, the case could serve as a roadmap for other states seeking to regulate UPFs.
The food industry did, however, find some cause for encouragement in a separate case decided in the Eastern District of Pennsylvania, where a motion to dismiss was granted with prejudice.
In that case, Martinez v. Kraft Heinz et al., the court found that allegations linking 179 UPFs made by 11 different manufacturers to Type 2 Diabetes and non-alcoholic fatty liver disease failed to establish product-specific causation.
The court also rejected the plaintiff’s industry-wide liability theories, underlining that private claims around ultra-processed foods still face steep legal hurdles despite growing public health concerns.
Together, these two cases signal that litigation over ultra-processed foods is rapidly evolving, with both government enforcement and consumer class actions testing the limits of existing legal frameworks.