This study experimentally investigates 1) whether ultra processed food (UPF) intake contributes to depression by increasing low mood and poor sleep due to blood glucose fluctuations (which then increases the desire to consume more UPFs) and 2) to investigate the effectiveness of a 2-week meal-kit intervention that provides convenient and tasty minimally processed foods (MPF) to reduce depression. The following aims and hypotheses are tested:

Aim 1: To investigate whether UPF intake and low mood contribute to each other in a cyclical fashion through the mechanisms of blood glucose fluctuations and disrupted sleep in individuals with moderate-to-severe depression.

H1: It is hypothesized that UPF intake and high blood glucose will be associated with low mood in individuals with depression.

Aim 2: To establish an industry partnership to investigate whether commercially available meal kit delivery reduces symptoms of depression in individuals with moderate-to-severe depression relative to a nutrition education control condition.

H2: Meal kit delivery will lead to reductions in depression symptoms and daily reductions in low mood relative to the control condition (nutrition guidance only).

The study will include a combination of in-person, at-home, and virtual activities over the course of ~21 days (contingent on scheduling, this duration may vary and particularly between in-person visits #1 and #2). Participants complete three in-lab visits, each followed by a week of remote data tasks (e.g., ecological momentary assessment, continuous glucose monitoring, and physical activity and sleep tracking (Fitbit)).

During in-lab visit #1, participants will complete questionnaires and interviews, have a continuous glucose monitor inserted, and will have body composition measurements taken (height, weight, Inbody scan). Participants will complete the remote tasks for the following week while eating their typical diet (i.e., baseline period).

During in-lab visit #2, participants will complete questionnaires, interviews, and body composition measurements (height, weight, Inbody scan). Participants are randomly assigned to a meal delivery (will receive two weeks of low UPF meals and nutrition guidance) or control (will receive some snacks and nutrition guidance) condition (i.e., dietary intervention period). Participants will complete the remote tasks for the following two weeks.

During in-lab visit #3, participants will complete questionnaires, interviews, and body composition measurements (height, weight, InBody scan).

Participants are contacted 1- and 6-months later to complete a short follow-up survey and provide information about their current diet.

Inclusion Criteria:

• 18+ years of age
• Must own an Android or iPhone smartphone
• Must be able to access phone one every 90 minutes
• Able to attend consent call over zoom or phone
• Endorsement of a PHQ-8 score of at least 10 assessed at consent
• Endorsement of a PHQ-8 score of at least 8 assessed 24 hours prior to Visit 1
• Endorse daily intake of at least UPF foods
• Willing to come to three in-lab visits
• Willing to follow dietary guidelines
• Must be able to speak, write, and read English fluently

Exclusion Criteria:

• Regular smoking of cigarettes or vaping of nicotine
• History of medication that impact reward, eating, or indicate severe mental health conditions (e.g., Lithium)
• The following medical conditions; Diabetes Type I, Diabetes Type II, Prediabetes, Bipolar Disorder, Schizophrenia, Psychotic Disorder, Depression with psychotic symptoms, Borderline Personality Disorder, Hypoglycemia, Substance use disorder (e.g., alcohol use disorder, opioid use disorder, cannabis use disorder), Obsessive compulsive disorder, and Post-traumatic stress disorder
• Endorsement of a suicide attempt or having been hospitalized for psychiatric reasons in the last year
• A diagnosis of a restrictive eating disorder (anorexia nervosa, bulimia nervosa, purging disorder) within the last 5 years
• History of disorders that impact eating (e.g., cancer, irritable bowel syndrome, inflammatory bowel disease, hypothyroidism).
• Current pregnancy, breast-feeding, trying to get pregnant, or within six months of having given birth
• Frequent (i.e., weekly) night shift work or irregular shifts and for abnormal sleep patterns (i.e., wake up time after 11am)

This research will generate demographic, heart rate, ecological momentary assessment, continuous glucose monitoring, self-report and anthropometric data. The data will be stored as SPSS or SAS files. Meta data will also be included in the selected repositories. The metadata will include the data dictionaries, which describe the generation of all variables. The deidentified data will be made available within one year of completion of the study at the University of Michigan's data repository - Deep Blue.

Beginning 1 year and ending 7 years following article publication

Researchers who provide a methodologically sound proposal will be able to access data to achieve aims outlined in the approved proposal. Proposals should be directed to agearhar@umich.edu to gain access. Data requestors will need to sign a data access agreement.

Participants will be blinded to their condition.