Meals that heal: a randomized controlled trial testing the feasibility of commercial meal delivery as a convenient dietary intervention for depression

Minimally processed dietary interventions have been associated with reductions in depressive symptoms; however, the effort required to plan, shop for, and prepare minimally processed foods may limit adherence. Providing convenient access to minimally processed meals through commercial delivery services may reduce these barriers and potentially enhance intervention impact. This pilot randomized study evaluated the feasibility, acceptability, and preliminary effectiveness of this novel approach through a two-week dietary intervention among adults with moderate to moderately severe depressive symptoms. After one week of baseline observation, participants (N = 31) received nutritional guidance on how to eat a more minimally processed diet for two weeks, which was either fully facilitated by commercial meal delivery (n = 20), or self-implemented (e.g., nutritional guidance; n = 11). Dietary quality (assessed via Diet ID) and depressive symptoms (assessed via PHQ-8) were evaluated through a combination of surveys administered remotely and during in-person laboratory visits at intake, pre-intervention, and post-intervention. Both approaches exhibited high feasibility, producing significant pre–post improvements in dietary quality across the total sample (d = 1.93). Pre-post reductions in depressive symptoms were observed in the meal delivery condition (d = 1.62), but not the nutritional guidance condition (d = .54); these between-group differences should be interpreted cautiously given the pilot design and limited statistical power. Within-person analyses for the total sample indicated that greater improvements in dietary quality were associated with larger reductions in depressive symptoms, with dietary quality explaining 17% of the variance in depressive symptoms (semi-partial R2 = .17). These findings provide insight into the potential of minimally processed dietary interventions for improving dietary quality and mental health and lay the groundwork for larger trials to assess longer-term effectiveness and sustainability.