In the Federal Register notice, officials ask the public to weigh in on some of the complicated details that often get discussed when it comes to what is and isn’t a UPF: Which physical processes should lead to a food being considered ultra-processed? Which ingredients on a label immediately make a food UPF, and does the amount in the food matter?

In an interview with Politico’s Dasha Burns over the weekend, Makary acknowledged that landing on a “perfect” definition will be difficult; he characterized the process as essentially figuring out where to draw the line between simple processing that doesn’t affect the healthfulness of a food (like chopping a cucumber) and industrial processing that does.

The agencies will take public comments until September 23. The process is likely to draw significant input from health and nutrition advocacy groups, food companies and their trade associations, and the agricultural groups that represent farmers growing crops that get turned into common UPF ingredients, such as corn and soy.

In the press release, the agencies said that when completed, the final definition “will allow for consistency in research and policy to pave the way for addressing health concerns associated with the consumption of ultra-processed foods.” That could include significant implications for school meals and food aid programs. While federal regulations in those programs don’t currently include restrictions on UPFs, several states have already begun passing laws that do, with Kennedy’s help.

“At a time when the cost of diet-related disease continues to grow, we welcome any effort to help consumers identify and avoid UPF and build healthier diets,” said Scott Faber, senior vice president for government affairs at the Environmental Working Group, in a statement. (Link to this post.)