California has once again stepped to the front of the regulatory line—this time in the school cafeteria. While Washington dithers over what exactly counts as an “ultra-processed food” (UPF), California’s Assembly Bill 1264 delivers the nation’s first legal definition for school meal programs, blending nutrition science, food chemistry, and public health into one sweeping mandate. Can law meaningfully define “junk food”? And what happens when one state decides it can?

While federal agencies have yet to issue a definition of ultra-processed foods (UPFs), California has moved ahead. Assembly Bill 1264, the first law of its kind, defines UPFs for school lunch programs as any product that contains at least one of seven types of additives, including colorants, emulsifiers, flavor enhancers, gases or propellants, stabilizers, thickeners, or surface-active agents. In addition, a product qualifies as ultra-processed if it either exceeds the state’s “high” thresholds for saturated fat, sodium, or added sugar, or if it contains a non-nutritive sweetener. [1] Certain foods—such as infant formula, raw produce, and unflavored milk—are specifically exempt. Under the law, the Office of Environmental Health Hazard Assessment (OEHHA) must identify particularly harmful UPFs by 2028; these products will be barred from sale to public schools after 2032 and entirely removed from school menus by 2035.

Does AB 1264 define nutrition?
Not entirely. The statute borrows the NOVA classification to determine the extent of processing, creating additive classes and nutrient ceilings, but it does not define a nutritious diet. It tells manufacturers what to take out, not children what to eat. NOVA, a research tool often regarded as the de facto standard, is translated into clearer, though not entirely clear, manufacturing criteria. The exclusions echo NOVA’s culinary ingredients (Group 2) as well as unprocessed and minimally processed foods (Groups 1 and 3). California’s UPFs echo NOVA’s Group 4, industrial formulations. In translating science into law, California also narrows the scope of concern by tying the level of processing to nutrient content.

Unlike the NOVA framework, which classifies foods solely by processing level, AB 1264 adds thresholds for sugar, fat, sodium, and sweeteners—linking the extent of processing to specific nutrient concerns. This hybrid model connects food manufacturing practices to aspects of nutritional quality but omits positives like fiber, protein, or micronutrients. For instance, a chocolate-coated protein bar could meet the law’s numeric limits while offering little whole-food value. Laws draw bright boundaries where nutrition science sees a spectrum. Measures like the Healthy Eating Index (HEI) capture overall diet quality more holistically, yet within the context of school meals, where sugar and sodium often dominate, California’s approach may be “nutritious enough.”

The Prop 65 Playbook – California’s Market Muscle

California’s Proposition 65 (Prop 65) requires the state to maintain and update a list of chemicals known to cause cancer and reproductive harm. The required “clear and reasonable” warnings are ubiquitous, reaching well beyond California as companies attempt to avoid litigation and control costs. California’s “Skittles-bill” banning red dye #3 and brominated vegetable oil has resulted in manufacturers reformulating their products, further evidence that what happens in California rarely stays in California. We can expect a similar trajectory with AB1264. 

California educates roughly one in eight U.S. public school students—about six million children—and is one of nine states [2] offering free meals to all. That market power gives its procurement rules enormous leverage. When the largest participant tightens its specs, suppliers notice.

Carton, can, and case runs are cheapest when formulas are uniform. Because food manufacturers prefer uniform production runs, few will make “California-only” formulas. Instead, they reformulate across the board. As with Prop 65, California’s size and influence make nationwide compliance the path of least resistance. In addition, other state legislators often copy California regulatory wording rather than drafting legislation from scratch. The resulting patchwork of state regulations will prompt manufacturers to seek relief from overarching federal regulation.

California is again using its market heft as a regulatory lever. As with Prop 65, sheer volume, economies of scale, and reputational optics make nationwide reformulation the simplest risk-management strategy for many brands. California’s definition of an ultra-processed food will soon influence ingredient and marketing claims far beyond the Golden State’s borders. Yet for all that market muscle, AB 1264’s legal footing may prove less sturdy than its political ambition.

Legal Gray Zones Ahead

While AB1264 uses state procurement rules to enforce its provisions, the ambiguity in the regulatory language ensures that litigation will follow. Among the easily identified concerns are the numerous undefined or subjective terms, which can lead to “arbitrary” enforcement. 

For example, “reputable peer-reviewed scientific evidence” may range from meta-analyses to single observational studies, with sources having inconsistent evidentiary weight. Or the term “common natural additive,” which comes with no compositional benchmarks. The absence of defined metrics would allow similar foods to be classified differently based solely on discretionary interpretation, a hallmark of arbitrary regulation.

The legislation requires consideration of whether the ingredients or foods

“are banned or restricted [or carrying a warning label] in other state, federal, or international jurisdictions due to concerns about adverse health consequences. … [or] based on reputable peer-reviewed scientific evidence, a substance or group of substances are linked to health harms or adverse health consequences.”

However, these terms are not defined. Are links statistical associations or causal inference? What authorities qualify as “reputable” or “peer-reviewed?” Moreover, the rule does not specify which jurisdictions count. One need only consider the controversy and litigation over toxicity claims by IARC compared to our FDA or EPA to recognize that this language is an open invitation to litigation. Will IARC’s determination become our national standard?

The inclusion of speculative conditions, e.g., “may contribute to food addiction,” further lowers the evidentiary bar. “Food addiction” lacks diagnostic consensus; any regulatory restriction grounded in this concept could be challenged as scientifically unsound and arbitrary.

Finally, the legislation requires consideration of:

“The quality, caliber, and scope of any scientific evidence … including a rigorous examination of whether such evidence is the product of scientific research conducted according to internationally recognized best practices for scientific research.”

But what are those standards? Are you talking about a Cochrane review, an “independent” panel of experts, with or without participation of all stakeholders, including manufacturers? An absence of a defined, legislatively described protocol opens up a host of litigation around administrative procedures that may lack adequate “transparency” or an agreed-upon standardized evaluation. 

Ultimately, the real test of AB 1264 may come not in school cafeterias, but in courtrooms.

Bottom line

AB 1264 may target school lunches, but its reach extends far beyond the cafeteria. California’s size and influence mean its purchasing rules often ripple through the entire U.S. food supply chain—just as Proposition 65 reshaped national labeling practices. Yet this bold experiment also tests how far states can go in translating complex nutrition science into law. Whether AB 1264 becomes a model for smarter policy or a cautionary tale of regulatory overreach will depend on how deftly California balances science, law, and practicality. One thing is sure: what’s happening on California’s lunch trays today could influence what the rest of America eats tomorrow.

[1] No more than 10% of total energy from saturated fats or added sugars; a ratio of milligrams of sodium to calories no greater than 1:1.

[2] The other states include Colorado, Maine, Massachusetts, Michigan, Minnesota, New Mexico, New York, and Vermont