In a 20-person UCSF pilot, cutting ultra-processed foods by 85% was followed by easing depression symptoms. Promising, and very small.

Here's a small study with a big question, and it deserves a careful read. Deseret News reports on a UC San Francisco pilot published in JAMA Psychiatry. Twenty adults with depression took part; most also had anxiety, and all had a high body mass index and at least one metabolic condition such as high blood pressure, diabetes or high cholesterol. Seventy percent were women, and the average age was 44. For four weeks, one group kept its usual diet while the other switched to a diet low in ultra-processed foods; then the groups traded places. Per the university's news release: "Participants reduced ultra-processed food intake by more than 85% and experienced moderate to large improvements across three measures of depression. Anxiety scores also improved modestly." The National Institutes of Health funded the work. Now the caveats, and they're big. Twenty people is a pilot, not proof, and everyone had several health conditions, so it's hard to say what drove the change. Senior author Dr. Andrew Krystal said the study "successfully established the viability of carrying out this research in a larger-scale trial," which UCSF plans to begin enrolling in 2028. Deseret notes other research has tied ultra-processed foods to cardiovascular disease, obesity and certain cancers, and an estimated 70% of the U.S. packaged food supply falls into that category. If you live with depression, keep your treatment plan and talk with your doctor before making big changes to your diet.