What it means
The term comes from the NOVA system, which groups foods by how much they are processed rather than by nutrients. Ultra-processed foods often contain ingredients rarely used in home cooking, such as flavorings, emulsifiers and modified starches, and are designed to be convenient and highly palatable.
In a 2019 NIH inpatient study, 20 adults spent two weeks on an ultra-processed diet and two weeks on a minimally processed diet with matched nutrients on offer. On the ultra-processed diet they ate about 500 more calories a day and gained about 2 pounds; on the other diet they lost about 2 pounds.
The study was small, and researchers are still testing why people overeat these foods. Not every processed food is a problem: canned beans, frozen vegetables and plain yogurt are processed but nutritious.
A practical goal is to build most meals around minimally processed foods and treat ultra-processed ones as occasional.
Why it matters
With a smaller appetite on a GLP-1, every bite counts more, so food quality matters for nutrients.