Low-Ultraprocessed-Food Diet Linked to Lower Depression Scores
Key Clinical Summary
- A randomized crossover pilot included 20 adults with major depression, high ultraprocessed food consumption, and at least 1 self-reported metabolic abnormality.
- Mean processed-food screening scores decreased from 10.10 at baseline to 1.42 after the intervention (P < .001).
- Depression and anxiety scores were significantly lower during the low-ultraprocessed-food period, but these outcomes were exploratory.
Reducing ultraprocessed food consumption was feasible and acceptable among adults with major depressive disorder (MDD) and was associated with lower depression and anxiety scores, according to a pilot crossover trial published via research letter in JAMA Psychiatry.
Researchers cautioned that the small, nonblinded study was designed primarily to assess feasibility—not clinical efficacy.
Study Findings
The study, conducted from June 2024 through June 2025, enrolled 20 adults aged 18 to 80 years. Eligibility criteria included a primary depression diagnosis, a Patient Health Questionnaire-9 (PHQ-9) score of at least 5, high ultraprocessed food consumption, and at least 1 self-reported metabolic abnormality.
The participants had a mean age of 43.7 years, 70% were female, and 70% had an additional anxiety diagnosis. All had high body weight and metabolic dysregulation. Nineteen participants completed the trial.
Investigators compared participants’ usual diets with a low-ultraprocessed-food diet using an open-label, order-randomized crossover design. Participants agreed not to change their medications, therapy, exercise, or sleep during the study.
Mean processed-food screening scores decreased from 10.10 at baseline to 1.42 following the intervention (P < .001). Participants rated the intervention’s ease at a mean of 5.74 and its utility at 8.42.
During the low-ultraprocessed-food period, mean PHQ-9 scores were 5.53 compared with 8.68 during the regular-diet period. The adjusted treatment difference was −3.12 (95% confidence interval [CI], −4.53 to −1.71; P < .001).
Significant differences also favored the low-ultraprocessed-food period on the Montgomery-Åsberg Depression Rating Scale (−10.78; 95% CI, −13.90 to −7.66; P < .001), Quick Inventory of Depressive Symptomatology (−3.67; 95% CI, −5.17 to −2.17; P < .001), and Generalized Anxiety Disorder-7 scale (−2.74; 95% CI, −4.51 to −0.98; P = .004). No adverse events occurred.
Clinical Implications
The findings establish that adults with depression and metabolic abnormalities can substantially reduce ultraprocessed food consumption within a clinical study. However, the moderate ease rating highlights the practical difficulty of making this dietary change.
The symptom findings should not be interpreted as definitive evidence that reducing ultraprocessed foods treats MDD. Depression and anxiety were exploratory rather than primary outcomes, and the study was small and nonblinded.
Researchers also could not determine whether the findings were associated with changes in macronutrients, calories, processing contaminants, or food additives. Ultraprocessed food intake was self-reported rather than objectively measured.
Expert Commentary
D. Nyasha Chagwedera, MD, PhD, Department of Psychiatry and Behavioral Sciences, University of California, San Franscisco, and colleagues characterized the mood findings as “exploratory and hypothesis generating at best.”
The authors called for larger, blinded studies incorporating objective dietary measures and assessments of possible mechanisms.
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