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

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.

Study Overview

• Status: Completed
• Conditions: Diet Quality; Time-restricted Eating
• Intervention / Treatment: Other: Time-restricted eating; Other: Current Best Practice

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 247
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Australia
  • South Australia
    • Adelaide, South Australia, Australia
      • South Australian Health and Medical Research Institute
  • Victoria
    • Melbourne, Victoria, Australia
      • Mary Mackillop Institute for Health Research

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 35 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

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:

Type 1 or type 2 diabetes, or diabetes detected at screening HbA1c ≥6.5% (48 mmol/mol).

• A personal history/diagnosis (self-reported) of:

  • 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), and 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.
• score on K10 ≥30 (Kessler Psychological Distress scale)
• score on EDEQ ≥2.8 (Eating Disorder Examination Questionnaire)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Time-restricted eating (TRE); 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; Time restricted eating for a self-selected 9 hour window per day
Active Comparator: Current Best Practice (CP); 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; Best practice guidelines to improve diet quality

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
HbA1c	Glycated haemoglobin concentration	baseline, 4 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
HbA1c	Glycated haemoglobin concentration	12 months
Fasting blood glucose	fasting blood glucose concentrations	baseline, 4 months, 12 months
Fasting insulin	fasting insulin concentrations	baseline, 4 months, 12 months
HOMA-IR	HOMA-IR	baseline, 4 months, 12 months
Nocturnal glucose	AUC of glucose assessed by CGM from midnight to 0400	baseline, 4 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Per protocol analysis	Per protocol analysis of data from participants who self-report adherence as 5-6 days per week or every day at 3.5 and 4 month adherence questionnaires ("adherent to the protocol")	4 months, 12 months
Body weight	body weight (assessed after an overnight fast, in a hospital gown)	baseline, 4 months, 12 months
Body composition	components of body composition assessed by DXA: fat mass (as percent body fat and kg), fat free mass (FFM, kg), visceral adipose tissue (VAT, g) and bone mass (kg)	baseline, 4 months, 12 months
Waist circumference	waist circumference (cm)	baseline, 4 months, 12 months
Hip circumference	hip circumference (cm)	baseline, 4 months, 12 months
Blood lipids	total, HDL and LDL cholesterol and triglycerides	baseline, 4 months, 12 months
hs-CRP	high sensitivity C-reactive protein (hs-CRP)	baseline, 4 months, 12 months
Liver markers	alanine transaminase (ALT) and aspartate aminotransferase (AST)	baseline, 4 months, 12 months
24h assessment of glycaemia	24h glucose measures assessed by CGM (including, but not limited to, time in range, CV)	baseline, 4 months
Physical activity	Components of activity (Step count, time in bed) assessed by inclinometer	baseline, 4 months, 12 months
Sleep duration	Sleep duration calculated from self-reported sleep/wake times	baseline, 4 months, 12 months
Cardiovascular measures	blood pressure and heart rate assessed using automated sphygmomanometer	baseline, 4 months, 12 months
meal timing / eating window	duration of eating window and individual meal times calculated from time-stamped food photos and/or self-reported meal times	baseline, 4 months, 12 months
Dietary intake	energy and macronutrient composition calculated from food diaries (research food diary app)	baseline, 4 months, 12 months
Adherence	measures of adherence assessed by self-report (questionnaire)	3.5, 4, 11.5, 12 months
Chronotype	participant chronotype calculated from MEQ-SA questionnaire	baseline, 3.5, 4, 11.5, 12 months
TRE vs CP on ambulatory blood pressure and renal function (sub-study)	Day and night time blood pressure (systolic, diastolic), dipping, morning surge, heart rate, blood pressure and heart rate variability. mesor, phase and amplitude of 24 hour ambulatory blood pressure monitoring; change in eGFR, creatinine, albumin urinary albumin:creatinine ratio, blood urea nitrogen and C-RP	baseline, 4 months
TRE vs CP on CGM outcomes in a subset of individuals with pre-diabetes (sub-study)	Change in CGM metrics (including 2 hour at-home glucose challenge) in participants with HbA1c >5.7% at baseline	4 months, 12 months
TRE vs CP on quality of life, mood, sleep and food preferences (sub-study)	Assessment of lifestyle using AQOL, mood using DASS-21 and CIA, sleep using PSQI and food preferences using NQOL and DRQOL	4 months, 12 months
TRE vs CP on diet quality (sub-study)	Assessment of changes in diet quality in TRE vs CP groups over 12 months using HEIFA (Healthy eating index for Australian Adults)	4 months, 12 months
TRE vs CP on barriers and enablers of adherence (sub-study)	Qualitative interview of a subset of participants to identify barriers and enablers of adherence to TRE vs CP advice	4 months, 12 months

Collaborators and Investigators

• Sponsor: University of Adelaide
• Collaborators: Australian Catholic University; La Trobe University
• Investigators: Principal Investigator: John Hawley, PhD, Australian Catholic University; Principal Investigator: Leonie Heilbronn, PhD, University of Adelaide

Publications and helpful links

Helpful Links

• preprint of the study protocol

Study record dates

Study Major Dates

• Study Start (Actual): February 17, 2021
• Primary Completion (Actual): August 2, 2023
• Study Completion (Actual): April 19, 2024

Study Registration Dates

• First Submitted: February 16, 2021
• First Submitted That Met QC Criteria: February 16, 2021
• First Posted (Actual): February 21, 2021

Study Record Updates

• Last Update Posted (Actual): August 2, 2024
• Last Update Submitted That Met QC Criteria: July 31, 2024
• Last Verified: July 1, 2024

More Information

Terms related to this study

• Other Study ID Numbers: 14023 (City of Hope Medical Center)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data that support the findings of this study will be available from the corresponding author for a period of 36 months from publication, upon reasonable request for academic use. The data will not be made publically available, as it contains information that could compromise research participant consent.
• IPD Sharing Time Frame: 36 months from date of publication
• IPD Sharing Access Criteria: Reasonable requests of data for academic use will be considered. Requests can be made to the corresponding author of the publication. Data will not be made publically available as it contains information that could compromise research participant consent.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No