The nation’s leading public health journal is laying down a marker for how it wants the Trump administration to define ultra-processed foods.

The guiding light for the administration, as it seeks to define highly processed foods and develop new food warning labels, should be a classification system called NOVA developed by a Brazilian researcher, say researchers who contributed to an edition of the American Journal of Public Health focused on the harms of ultra-processed food.

The NOVA system categorizes food by its additives and industrial processing, instead of nutritional content. The researchers said the approach – which defines ultra-processed food as including little to no whole foods or ingredients used in home kitchens and intensely processed – is the best way to ensure no foods slip through the definitional cracks.

“It’s important to get the federal definition right, because everything will flow from that,” said Lindsey Smith Taillie, a nutrition epidemiologist at the University of North Carolina.

Health Secretary Robert F. Kennedy Jr. has vowed to define ultra-processed food and create a new front-of-package warning label for consumers, as part of his promise to help Americans eat healthier and avoid foods that make them heavier and sicker.

Some states, including politically red ones, have also moved to ban foods with certain additives and dyes from school and food assistance programs, as support for stricter food regulation has become more popular even among conservatives.

Kennedy had promised a definition by April, but the administration has disclosed little about when one will be ready or how narrowly or broadly it will define such foods. The government requested public input last year.

“The FDA is reviewing the comments following the request for information to help inform next steps,” HHS spokesman Andrew Nixon said in a statement.

Taillie said she and her colleagues have shared their research with the Food and Drug Administration, the agency charged with defining ultra-processed foods. Their research – published Wednesday in the American Journal of Public Health – includes nearly two dozen research briefs, editorials and essays exploring the detrimental effects of the nation’s highly commercialized processed food system.

“Ultra-processed food is food that is not made with real food,” said Carlos Monteiro, an epidemiologist at the University of Sao Paulo who developed NOVA.

NOVA has overwhelming support among researchers and is used as the dominant framework in academic literature. It divides food into four categories, ranked from not at all processed to ultra-processed. Foods that fall into that ultra-processed category – which include things like potato chips and sodas and even some sandwich breads – are what primarily concern policy makers and nutritionists.

Yet the NOVA system has some critics, too. They include food industry-funded researchers who argue the definition of ultra-processed foods is too broad and nutrition scientists who want a more nuanced system that doesn’t penalize certain processed foods like fortified cereals or plant-based proteins.

Monteiro wrote in one essay that the NOVA system has been used not only in Brazil but in 14 other countries. He says that by emphasizing food processing, the system helps to communicate how food is made, what food is made from and who makes it.

Taillie said states that have used other ways of defining ultra-processed food “only capture a small fraction of the ultra-processed foods in the food supply.”