What Or When to Eat to Reduce the Risk of Type 2 Diabetes (WOW)

Study Overview
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Brief Summary
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A parallel, single-blinded, multi-centre randomized controlled trial conducted at the South Australian Health and Medical Research Institute (SAHMRI) and the Mary Mackillop Institute for Health Research (MMIHR; Australian Catholic University), by researchers from the University of Adelaide, Australian Catholic University and La Trobe University.

Detailed Description
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In a parallel groups design, a total of 268 individuals will be recruited across both sites. After a 2-week baseline period, and a baseline metabolic visit, participants will be randomized into one of two groups (TRE, time-restricted eating; CP, current practice guidelines). All participants will receive five (5) telehealth consultations at baseline, week 2, 4, 8 and 12, the content of which will be based around their randomized condition. They will undergo metabolic testing on two (2) further occasions (4 months, 12 months) over a 12-month period to assess the changes in primary and secondary outcomes.

Official Title
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What Or When to Eat to Reduce the Risk of Type 2 Diabetes (WOW)

Conditions
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Time-restricted Eating, Diet Quality

Intervention / Treatment
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* Other: Time-restricted eating
* Other: Current Best Practice


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Study participants will be aged 35 to 70 years, overweight or obese (BMI: >25 but <45 kg/m2), ≥15 on the AUSDRISK assessment tool and have HbA1c <6.5% at screening Exclusion Criteria: A personal history/diagnosis (self-reported) of: diabetes (type 1 or 2) major psychiatric disorders (schizophrenia, major depressive disorder, bipolar disorder, eating disorders) gastrointestinal disorders/disease (including malabsorption) haematological disorders (i.e. thalassemia, iron-deficiency anaemia) insomnia currently receiving, or have received treatment/diagnosis of cancer in the past 3 years (excluding non-melanoma skin cancer) significant liver or kidney disease previous or planned gastro-intestinal surgery (including bariatric surgery) Congestive heart failure (NYHA stage 2 or above) Previous myocardial infarction or significant cardiac event ≤ 6 months prior to screening Previous cerebrovascular event ≤ 12 months prior to screening and/or any other condition deemed unstable by the study physician. Currently taking the following medications: any medication used, or known to lower blood glucose, or antidiabetic medications, including, but not limited to: SGLT2 inhibitors, metformin, sulfonylureas, glucagon-like peptide-1 (GLP-1) analogues [i.e. exenatide], thiazolidinediones or DPP-IV inhibitors [i.e. 'gliptins']) Medications affecting weight, appetite or gut motility, including, but not limited to: (domperidone, cisapride, orlistat, phentermine, topiramate). Diuretics (i.e. frusemide, thiazides) or combination blood pressure medications containing a diuretic Beta-blockers Glucocorticoids Anti-epileptic medications Antipsychotic medications Opioid medications unless combined with paracetamol in a single formulation and used occasionally on a PRN basis Additional exclusion criteria include: do not consume a regular breakfast (i.e. eat breakfast on an average of 5 or more days per week), OR do not eat for more than 12 hours per day on an average of 5 or more days per week have an extreme or restricted pattern of eating (i.e. following an intermittent fasting diet) or are already engaged in a TRE protocol shift-workers pregnant, planning a pregnancy or currently breastfeeding those who have lost or gained >5% of body weight in the last 6 months current smokers of cigarettes/marijuana/e-cigarettes/vaporisers anyone unable to comprehend the study protocol or provide informed consent (i.e. due to English language or cognitive difficulties) Participants will not have seen a dietitian in the preceding 3 months.

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Time-restricted eating (TRE)<br>The TRE group will be instructed to follow TRE (9 h/day) every day for 12 months with no other dietary instructions or advice provided. The TRE group will attend the same consult schedule as the CP group, but consultations will focus on timing of dietary intake and strategies to promote adherence. No dietary guidance regarding quantity or quality will be provided. Participants will be able to self-select the precise 9-h schedule that will best suit their lifestyles, with the caveat that the latest time of eating will be set at 7:00 pm. Outside of the elected eating window, participants will be allowed to consume water and black coffee and/or tea. | Other: Time-restricted eating<br>* Time restricted eating for a self-selected 9 hour window per day<br>|
| Active Comparator: Current Best Practice (CP)<br>This group is designed to act as a comparator using 'standard care' in dietetics practice. Dietary advice provided to this participant group will be performed by Accredited Practicing Dietitians (APDs) in line with evidence-based guidelines, specifically the T2DM best-practice guidelines plus Australian Dietary Guidelines (i.e. Australian Guide to Healthy Eating) to improve diet quality, and strategies to promote adherence. No specific advice will be provided regarding time of day to start and finish eating and/or drinking (since this information is not outlined in current practice guidelines). | Other: Current Best Practice<br>* Best practice guidelines to improve diet quality<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| HbA1c | Glycated haemoglobin concentration | 4 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| HbA1c | Glycated haemoglobin concentration | 12 months | 
| 24-hour glucose variability | Assessment of 24 hour glucose variability by continuous glucose monitor | 4 months | 
| Body weight | change in body weight | 4 months, 12 months | 
| Body composition | change in percent body fat, fat free mass by DXA | 4 months, 12 months | 
| Waist circumference | change in waist circumference | 4 months, 12 months | 
| Hip circumference | change in hip circumference | 4 months, 12 months | 
| Fasting blood glucose | Change in fasting blood glucose concentrations | 4 months, 12 months | 
| Fasting insulin | Change in fasting insulin concentrations | 4 months, 12 months | 
| Blood lipids | Change in total, HDL and LDL cholesterol and triglycerides | 4 months, 12 months | 
| Physical activity | Changes in activity assessed by inclinometer | 4 months, 12 months | 
| Adherence | measures of adherence assessed by self-report | 0.5, 1, 2, 3, 4, 8, 12 months |