California has become the first state in the nation to ban ultraprocessed food ingredients from school meals, following the signing of a groundbreaking new law by Governor Gavin Newsom. The legislation, approved with bipartisan support, will phase out ultraprocessed ingredients from K–12 school breakfasts and lunches over the next decade. It marks a major shift in public health policy by focusing not just on calories, fat, or sodium, but on the degree and nature of food processing itself.

Under the new law, the California Department of Public Health will develop a legal definition of “ultraprocessed” and identify specific additives, dyes, sweeteners, emulsifiers, and other compounds that will be prohibited. Schools will then have ten years to eliminate those ingredients from the meals they serve. Advocates say this step reflects growing scientific consensus that ultraprocessed foods, though often inexpensive and convenient, are linked to higher rates of obesity, diabetes, heart disease, and even certain cancers.

Researchers have documented how diets high in ultraprocessed foods affect children in particular. Because kids consume a large portion of their daily calories at school, what is served in cafeterias can shape lifelong eating habits. Supporters of the law argue that California’s massive school meal system, which serves nearly a billion meals a year, has the power to influence national food manufacturing standards. If California schools stop buying certain products, they say, major food companies will be forced to reformulate recipes to keep contracts.

The law comes at a time when the Los Angeles Unified School District, the largest district in the state, has already been taking steps to improve school meals and reduce reliance on heavily processed items. LAUSD’s food services division has spent years increasing scratch cooking, sourcing local produce, and removing artificial dyes and preservatives. Nutrition advocates see the new law as a way to build on that progress and ensure consistency across all California districts, especially those with fewer resources than LAUSD to make such changes on their own.

Still, challenges lie ahead. Some food industry groups have warned that defining “ultraprocessed” will be complicated and may unintentionally exclude otherwise healthy foods such as whole-grain breads or meat alternatives that use binders. School nutrition directors worry about the costs of sourcing new ingredients and retraining staff. Others point to the risk of deepening inequities if wealthier districts adapt more quickly than underfunded ones. To ease that transition, the law allows for gradual implementation over a decade, giving schools time to adjust menus and supply chains.

The measure reflects a growing movement to scrutinize not just what nutrients are in food, but how food is made. California’s action is expected to influence national conversations about the role of food processing in chronic disease and child health. Public health experts say the law could become a model for future regulations nationwide, much as California’s earlier bans on trans fats and soda sales in schools helped shape federal standards.