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Evaluation of a dietary pattern in healthy volunteers: A proof-of-concept trial

Evaluation of a dietary pattern in healthy volunteers: A proof-of-concept trial

Status
Recruiting
Phases
Unknown
Study type
Interventional
Source
ANZCTR
Registry ID
ACTRN12624000108516
Enrollment
5
Registered
2024-02-08
Start date
2024-03-12
Completion date
2026-12-31
Last updated
2025-09-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

OPTIMISM is a 4-week double-blind placebo-controlled feeding trial. All meals and snacks will be provided to participants for the duration of the study. In total, 22 healthy volunteers will be recruited along with 44 adults with a major depressive disorder (see linked record). Study visits will be conducted at baseline and week 4 at either the Health Education and Research Building (HERB), Barwon Health, Geelong, or at the Alfred Centre, Monash University, Melbourne.

Interventions

Participants will attend study visits in-clinic at baseline and week 4 at the Health Education and Research Building (HERB), Barwon Health, Geelong or at the Alfred Centre, Monash University, Melbourne. A whole-diet intervention that provides a balance of protein, carbohydrate and fat will be provided to participants for 4 weeks. A 7-day meal plan, which meets the food group targets of the intervention diet, was developed for two energy levels (Level 1 - 8MJ/day, Level 2 - 10MJ/day). Participant

Participants will attend study visits in-clinic at baseline and week 4 at the Health Education and Research Building (HERB), Barwon Health, Geelong or at the Alfred Centre, Monash University, Melbourne. A whole-diet intervention that provides a balance of protein, carbohydrate and fat will be provided to participants for 4 weeks. A 7-day meal plan, which meets the food group targets of the intervention diet, was developed for two energy levels (Level 1 - 8MJ/day, Level 2 - 10MJ/day). Participants will be allocated to Level 1 or Level 2 based on an assessment of their habitual diet at baseline by a dietitian and may be adjusted at subsequent weekly calls to meet an individual’s energy requirements, based on dietetic assessment (e.g. assessment of individual’s weight, hunger levels). Three meals and three snacks will be provided to participants each day for the duration of the study. Participants will receive dietary information one-on-one from a dietitian at baseline and will be provided with a study booklet developed for the purpose of the study. One-on-one baseline and week 4 visits will be approximately 2 hours in duration each. During the intervention, participants will meet weekly with a study investigator (dietitian) online which will be approximately 20 minutes in duration. Diet adherence will be assessed via the completion of daily food adherence logs which will be returned to researchers at the final study visit.

Sponsors

Monash University
Lead SponsorUniversity

Study design

Allocation
Non-randomised trial
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject)

Eligibility

Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
Yes

Inclusion criteria

• Adults aged 18-65 years • Poor quality diet (as rated by an adapted Total Diet Score) • Willing to undertake and adhere to a 4-week feeding trial (willing to consume study meals provided) and attend all study appointments • Reside in meal delivery zones • Must be able to read and understand materials written in English • Have access to a smartphone/tablet/computer with internet access and kitchen facilities (e.g., microwave/oven, freezer) • Must nominate a preferred general practitioner

Exclusion criteria

• Mild, moderate or severe depressive symptoms based on score greater than or equal to 7 on MADRS • Participants with current suicidal ideation with a specific plan, defined as a score of 5 or 6 on the MADRs item 10 • Current clinician-diagnosed major depressive disorder reported by participant or requiring medication and/or other treatment for depression • Diagnosis of complex medical disorder (e.g., cancer, type 1 and 2 diabetes, dementia, heart failure, chronic obstructive pulmonary disease • History of major GI surgery (e.g., gastrectomy, colectomy) • Clinician-diagnosed irritable bowel syndrome or inflammatory bowel disease reported by participant • Clinician-diagnosed bipolar I or II disorder, psychotic disorder or personality disorder reported by participant • Clinician diagnosed substance use disorder reported by participant and/or excess alcohol intake (>10 standard drinks per week or >4 standard drinks on any one day standard drinks/week) • Clinician diagnosed eating disorder reported by participant or score greater than or equal to 3 on the SCOFF eating disorder screening questionnaire or history of purging, binge eating or laxative abuse • Dietary restrictions, food allergies, intolerances or aversions, that would interfere with consuming intervention foods (I.e., food allergy coeliac disease, veganism, lacto-ovo vegetarianism) • Sociocultural, religious, medical reasons which precludes participation • Females who report to be pregnant or breastfeeding • Individuals who exceed the minimal physical activity guidelines of 150 min/wk or underweight (BMI <18.5 kg/m2) or class III obesity (>40 kg/m2) or unstable weight (loss/gain) over the past 3 months (> 5%) (as energy intake requirements will be more difficult to achieve) • Current participation in another clinical trial • Probiotic, prebiotic and/or synbiotic supplementation in the past 4 weeks • Antibiotic use in the past 4 weeks

Outcome results

None listed

Source: ANZCTR · Data processed: Feb 4, 2026