Litigation over ultra-processed foods (UPFs) continues to proliferate, including a significant new government enforcement action. There is no legal definition of UPFs, but, in simplest terms, UPFs have one or more ingredients not found in an ordinary kitchen, such as modified starches, emulsifiers, and chemical preservatives. Most UPFs are engineered to be energy dense (i.e. high calorie), highly palatable, convenient, and quickly consumed. Common examples include chips, soda, processed meats, boxed macaroni and cheese, and some breakfast cereals.
On Dec. 2, 2025, the San Francisco City Attorney sued nine large food manufacturers of alleged UPFs[1]. The complaint alleges violations of California’s Unfair Competition Law (UCL), Cal. Bus. & Prof. Code § 17200 et seq., and public nuisance law based on claims that defendants allegedly engineered addictive UPFs, targeted minority and low-income communities, and concealed known public health harms.
By framing UPF as the cause of societal harm ripe for government enforcement, rather than a private injury claim, the focus shifts away from proving multi-factorial individual injury to deleterious impact on public health. This government framing affects potential remedies, because a government plaintiff may seek “abatement” of an alleged public nuisance without tying liability to one person’s injury. Similar strategies have been used in lead paint litigation. The city of San Francisco’s case may also seek significant monetary compensation and seek to require modification to the way packaged foods are made and marketed. The industry, including the Consumer Brands Association, has criticized the suit, arguing that companies complying with federal food-safety and labeling rules should not face public nuisance liability. If the UCL and public nuisance theories survive dispositive motions, this case may serve as a roadmap for other states seeking to regulate UPFs under state law. And state courts will be the battlegrounds; this matter was remanded to California state court on April 23, 2026, because the diversity jurisdiction could not be maintained where the state was the real party in interest.
On the consumer class action front, a recent victory at the motion to dismiss stage in the Eastern District of Pennsylvania[2] may offer an encouraging sign for the food industry. In granting the motion with prejudice, the court held that allegations linking 179 UPFs made by 11 different manufacturers to Type 2 Diabetes and non-alcoholic fatty liver disease did not plausibly establish product-specific, but-for causation on a product-by-product basis. The court also rejected plaintiff’s industry-wide liability theories. This decision highlights that even against a backdrop of broader public-health concerns around UPFs, private claims presently face steep causation hurdles.
[1]People of the State of California v. Kraft Heinz et. al., No. CGC-25-631189 (Cal. Super. Ct.) (2025).
[2]Martinez v. Kraft Heinz, et al., Case No. 2:25-cv-00377 (E.D. Pa.)