Regulation of, and litigation over, ultra-processed foods (UPFs) is expected to gain traction in 2026. Mounting evidence linking UPFs to chronic diseases, including obesity, type 2 diabetes and fatty liver disease is intensifying regulatory scrutiny and fuelling litigation. Political rhetoric, including references to UPFs as 'poison' has emboldened US states to introduce restrictions on UPFs. While federal regulation remains uncertain, the US Food and Drug Administration (FDA) and the US Department of Agriculture (USDA) are actively considering a uniform definition, which is expected to provide greater legal and regulatory certainty regarding the scope of UPFs. UPF class actions and personal injury claims are increasing, targeting alleged deceptive marketing and the intentional design of UPFs to be 'hyper palatable' or addictive. However, plaintiffs will continue to face significant challenges in establishing causation, with alternative legal theories being explored. The forthcoming FDA/USDA definition is likely to spark further claims activity and heighten exposure for food manufacturers and distributors.