In December 2024, a Philadelphia courtroom became the battleground for a legal first: Martinez v. Kraft Heinz et al., the nation’s first major lawsuit targeting ultra-processed food (UPF) manufacturers. Bryce Martinez, a teenager diagnosed with type 2 diabetes and non-alcoholic fatty liver disease, claims that his health was compromised by years of consuming foods engineered to be hyper-palatable and addictive. The lawsuit names 11 food conglomerates, including Nestlé, PepsiCo, and Coca-Cola, alleging negligent design, failure to warn, and deceptive marketing—a playbook reminiscent of Big Tobacco litigation. But the case faces a familiar evidentiary obstacle: the Daubert standard.

The Daubert Dilemma in Nutrition Litigation

Adopted by federal courts and many states, the Daubert standard requires that expert testimony be grounded in scientific methods that are testable, peer-reviewed, have known error rates, and enjoy general acceptance in the scientific community. This threshold poses a substantial challenge for nutrition science, which leans heavily on observational epidemiology to link UPFs to chronic diseases. As with many public health issues, randomized controlled trials are rare due to ethical and logistical barriers. The result is a disconnect: what is sufficient evidence for regulatory or public health action may fall short in courtrooms demanding individualized causation and mechanistic certainty.

Correlation, Not Causation: A Legal Science Mismatch

The National Institutes for Health (NIH) in the US funded a study (Hall et al., 2019) which demonstrated that UPF-heavy diets can cause weight gain and increased calorie intake in just two weeks, offering rare causal evidence. Yet most research relies on population-level data, which courts often view as insufficient under Daubert. For example, meta-analyses have linked each 10% increase in UPF consumption to a 12% rise in type 2 diabetes risk and significantly higher rates of cardiovascular disease and all-cause mortality (Lane et al., 2024). However, judges may discount these associations as correlative rather than causative, especially when plaintiffs like Martinez must prove that specific products from multiple companies directly caused specific health outcomes.

FDA Labeling Reforms Face Similar Scientific Constraints

The evidentiary gap impacts not only the courts but also regulatory agencies. The FDA’s updated “healthy” labeling rule, effective February 2025, excludes many UPFs due to their high added sugar, sodium, and low whole-food content. However, the rule sidesteps the term “ultra-processed” entirely, reflecting the agency’s reliance on nutrient profiling rather than processing levels—in part because UPF classifications like NOVA are not universally recognized by U.S. regulators (FDA, 2024). Proposed front-of-package labeling may include warnings for added sugars and sodium, but still stops short of confronting processing as a health risk category.

Lessons from Tobacco: Similarities and Limits

The Martinez complaint mirrors tactics used against tobacco companies, including claims of addiction by design, internal industry knowledge, and targeted marketing to youth. Historical ties between tobacco firms and food companies strengthen this analogy. However, food lacks the binary risk profile of tobacco; it is essential, not inherently harmful. Courts may find it harder to assign liability when harm depends on dose, context, and individual behavior. Unlike tobacco, where causation and risk were eventually established through internal documents and statistical modeling, UPF litigation lacks decades of insider memos and clearer mechanistic pathways.

Toward a More Realistic Evidentiary Standard

The evidentiary gulf between nutrition science and the courtroom is unlikely to close any time soon. While regulators adapt by leaning on population-level data and weight-of-evidence frameworks, the legal system continues to demand individualized proof that nutrition studies rarely provide. As more cases like Martinez v. Kraft Heinz emerge, the courts are likely to remain cautious, limiting plaintiffs’ success unless stronger causal evidence is produced. This mismatch may not just stall litigation—it could stall progress. Until science, regulation, and law converge on a shared evidentiary language, UPF accountability will remain elusive, and the burden will continue to fall on the consumer.

References

Hall, K. D., et al. (2019). “Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake.” Cell Metabolism, 30(1), 67-77. https://www.bmj.com/content/384/bmj-2023-077310

Lane MM, Gamage E, Du S, Ashtree DN, McGuinness AJ, Gauci S, et al. 2024. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 384:e077310. https://doi.org/10.1136/bmj-2023-077310

U.S. Food and Drug Administration (FDA). 2024. Food labeling: nutrient content claims; definition of term “healthy.” Federal Register. 89(249):93629–93659. https://www.federalregister.gov/documents/2024/12/27/2024-29957/food-labeling-nutrient-content-claims-definition-of-term-healthy