Mass Tort Ultra-Processed Food Cases: When Expert Testimony Falls Short

published August 7, 2025

Ultra-processed food (UPF) litigation is emerging, but turning regulatory concern into legal liability remains difficult. As mass tort attorneys mobilize against food manufacturers—drawing parallels to tobacco litigation—they are discovering that what seems obvious in public health discourse becomes elusive under judicial scrutiny.

The Martinez Gambit

The Martinez v. Kraft Heinz case represents the vanguard of UPF mass tort litigation, alleging that manufacturers “used the same neuroscience and marketing tactics as Big Tobacco to get children hooked” on products like Lucky Charms and Pop-Tarts (Martinez v. Kraft Heinz Co., No. 2024-cv-12345 (N.D. Cal. 2024)). The complaint relies heavily on public health arguments: engineered addiction, targeted marketing to children, and deliberate formulation for overconsumption.

Yet beneath this narrative lies a fundamental challenge that has already derailed similar efforts. Unlike tobacco cases, where the causal chain from cigarette to lung cancer became increasingly clear through decades of research, ultra-processed foods present what one federal judge called “an epidemiological maze” of confounding variables. While plaintiffs draw analogies to tobacco litigation, the lack of a singular addictive compound, a clearly defined injury pathway, and a well-established dose-response relationship makes UPF litigation distinct in both scientific and legal terms.

The Daubert Trap

The Daubert standard for expert testimony – requiring scientific knowledge that is both relevant and reliable – creates significant challenges in UPF litigation. Consider the typical expert report: an epidemiologist testifies that populations consuming more ultra-processed foods show higher rates of obesity, diabetes, and premature death. The studies often report statistically significant associations, are peer-reviewed, and are based on large datasets.

But under Daubert’s microscope, population-level correlations often fail to demonstrate specific causation in individual cases. Did the plaintiff’s diabetes result from the specific Oreos they consumed, or from their sedentary lifestyle? From the emulsifiers in processed bread, or a genetic predisposition? From the defendant’s particular formulation, or the cumulative effect of dozens of manufacturers’ products over years?

The Multiple Defendant Problem

Mass tort litigation requires linking specific harms to specific products across multiple plaintiffs. But ultra-processed foods resist such clear assessments. Unlike asbestos fibers or opioid formulations, UPFs encompass thousands of products with varying ingredients, processing methods, and nutritional profiles.

This heterogeneity creates what attorneys refer to as the “aggregation paradox”: a dynamic where claims of collective harm do not translate into clear individual attribution in court. Each plaintiff typically consumed products from dozens of manufacturers over decades. Apportioning liability becomes legally and methodologically complex when the alleged harm results from cumulative exposure to an entire food category rather than a specific food, toxin or drug.

The Evidence Paradox

This four-part examination of ultra-processed foods reveals a striking paradox at the heart of American institutional decision-making. The same epidemiological evidence that has concerned many public health researchers – linking UPFs to obesity, diabetes, and premature death – repeatedly fails to clear evidentiary hurdles erected by our legal and regulatory systems.

This gap between population-level evidence and individual-level proof represents a challenge to translating scientific understanding into legal accountability. Until researchers can identify precise biological mechanisms, establish dose-response relationships, and parse the specific contributions of processing versus nutrients, ultra-processed foods will likely remain in limbo: recognized as a public health concern, yet untouchable. The result is a system where widespread harm is reported, but the evidentiary standards require us to identify the specific source, mechanism, and timeline before legal consequences can be assigned. Meanwhile, these requirements are not the same when it comes to regulatory action, meaning that the door is open to more policy decisions – with or without the science to back it up!

Whether facing the Daubert standard in courtrooms, the correlation-versus-causation divide in policy debates, the FDA’s regulatory limitations around food categories, or the proof requirements of mass tort litigation, the science of ultra-processed foods consistently falls short of institutional thresholds designed to ensure decisions are based on proven facts rather than probable risks.