An interventional study of eCR and dCR in Obesity, sponsored by University of Adelaide. Completed at 1 site in Australia. Open to participants aged 35 Years to 75 Years. Per ClinicalTrials.gov, last updated 2025-05-09.
Sponsored by University of Adelaide · Not applicable, Interventional, and Basic science
Type 2 diabetes and cardiovascular disease are an increasing problem in Australia and around the world, and are partly linked to increased rates of obesity, together with sedentary lifestyles. This study will compare caloric restriction (CR) diets that restrict the amount of food that is eaten with CR diets that also restrict the time that the food is eaten, to either early or late in the day, on risk factors for type 2 diabetes and cardiovascular diseases over 2 months.
In a parallel groups design, a total of 114 individuals will be recruited. After a two-week lead in and collection of data from activity monitors and continuous glucose monitors, plus a 28 hour (h) metabolic ward in-patient stay, participants will be randomised into one of three groups (eCR, 8-hour early time restriction + calorie restriction (e.g. 8:00-16:00); dCR, 8-hour delayed time restriction + calorie restriction (e.g. 12:00-20:00); CR, caloric restriction (>12 hour eating window (e.g. 8:00-20:00). All participants will receive individualised menus and foods that will be delivered to their homes by a supermarket delivery service at energy balance for 1 week (baseline) and at 70% of energy balance for a further 8 weeks. Repeat assessment occurs from 6-8 weeks with the final metabolic ward stay at 8-weeks to assess changes in primary and secondary outcomes.
There are three preplanned sub-studies from the parent trial:
A. OMIT-Immune sub-study All participants will have blood samples collected at six timepoints over 24 hours and stool samples will be collected at two timepoints in a subset. The aims of this sub-study are to 1) characterize the changes in 24 h rhythm (mesor, amplitude and acrophase) of immune cells by flow cytometry over 24 hours, 2) describe the changes in the diversity of bacterial in response to intervention and 3) compare the effects of 8 weeks of CR versus eCR and dCR on immune profiles and gut microbiome.
B. OMIT-BP sub-study All participants will have blood and urine samples collected at six timepoints over 24 hours. A subset of participants will wear 24 h ambulatory blood pressure monitors. The aims of this sub-study are to compare the effects of CR versus eCR and dCR on 1) the 24-hour profile of blood pressure assessed by ambulatory blood pressure monitoring, 2) Plasma markers of blood pressure regulation and 3) markers of renal function. We hypothesise that both eCR and dCR will alter and enhance these parameters and markers in comparison to CR. Changes in the circadian mesor, amplitude and acrophase in: systolic blood pressure, diastolic blood pressure, heart rate, pulse pressure, mean arterial pressure, nocturnal blood pressure dipping, morning blood pressure surge, plasma renin, aldosterone, creatinine, Urinary potassium, sodium, cortisol, creatinine.
C. OMIT- Six month follow up. All participants will be instructed to continue their respective diet intervention and return to the clinic after an additional 16 weeks for a fasting blood sample and assessment of body composition. The aims of this sub-study are to 1) compare the 6 months effects of CR versus eCR and dCR on body composition and fasting blood samples metabolic health from baseline; 2) explore the factors that drive the intention-behaviour gap (describing the failure to translate intentions into action) relation to diet adherence. We hypothesize that participants will maintain the intervention-induced improvements in behavioural and metabolic health outcomes. Additionally, changes in body weight, waist and hip circumference, lean mass, fat mass, blood pressure, glycated hemoglobin, fasting plasma glucose, insulin, total cholesterol, LDL, HDL, triglycerides are assessed.
University of Adelaide is the lead sponsor of 42 studies on the registry; 6 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
A personal history/diagnosis (self-reported) of:
Currently taking the following medications:
Individuals will be provided with menus prescribed at 70% of calculated energy requirements and instructed to eat within 8 h/day (e.g. 8:00 - 16:00) every day for 8 weeks, except 1 evening meal per week off the program (i.e. Saturday nights) to assist with overall adherence.
Other: eCR
Individuals will be provided with menus prescribed at 70% of calculated energy requirements and instructed to eat within 8 h/day (e.g 12:00 - 20:00) every day for 8 weeks, except 1 evening meal per week off the program (i.e. Saturday nights) to assist with overall adherence.
Other: dCR
Individuals will be provided with menus prescribed at 70% of calculated energy requirements every day for 8 weeks. The menus will encourage breakfast and after-dinner consumption of the snack to eat over at least a 12 hour time frame per day (e.g. 8:00 - 20:00), except 1 evening meal per week off the program (i.e. Saturday nights) to assist with overall adherence.
Other: CR
Eating time window from 8:00 to 16:00
Eating time window from 12:00 to 20:00
Eating time window from 8:00 to 20:00
Glucose area under curve (AUC) after 3 meals
Change in glucose AUC after 3 meals
Time frame: 8 weeks
Insulin area under the curve (AUC)
Change in insulin AUC (sum of 3 meals)
Time frame: 8 weeks
Fasting insulin
Change in fasting insulin
Time frame: 8 weeks
Fasting glucose
Change in fasting glucose
Time frame: 8 weeks
Change in glycated hemoglobin (HbA1c)
Change in glycated hemoglobin
Time frame: 8 weeks
Postprandial glucose and insulin AUC of each meal
Postprandial glucose and insulin AUC of breakfast, lunch, dinner
Time frame: 8 weeks
Non-esterified fatty acids (fasting, postprandial AUC)
Change in free fatty acids fasting, postprandial AUC of each meal, and sum of 3 meals
Time frame: 8 weeks
Triglycerides (fasting, postprandial AUC)
Change in triglycerides as fasting, postprandial AUC of each meal, postprandial AUC sum of 3 meals
Time frame: 8 weeks
Insulin secretion rate
calculated from C-peptide response to each meal, and overall
Time frame: 8 weeks
Insulin sensitivity (calculated by Matsuda index where a higher score means greater insulin sensitivity)
Change in insulin sensitivity
Time frame: 8 weeks
24 h glucometrics on ward (by continuous glucose monitor [CGM])
Change in 24 h glucose on ward by CGM (iAUC, mean nocturnal glucose \[2400-0400\], ,mean, time in range, time above range, time below range, mean amplitude of glycemic excursions \[MAGE\])
Time frame: 8 weeks
HOMA-IR
Change in HOMA-IR calculated as \[fasting insulin ug/ml\]\*\[fasting glucose mmol/L\]/22.5
Time frame: 8 weeks
Fasting C-peptide
change in fasting C-peptide
Time frame: 8 weeks
Total cholesterol
Change in total cholesterol
Time frame: 8 weeks
HDL cholesterol
Change in HDL cholesterol
Time frame: 8 weeks
LDL cholesterol
Change in LDL cholesterol
Time frame: 8 weeks
C-reactive protein (CRP)
Change in hs-CRP
Time frame: 8 weeks
Physical activity by activity monitor
Change sitting time, standing time, stepping time, mean daily steps
Time frame: 8 weeks
Sleep metrics
Change in sleep metrics (including sleep duration, sleep latency, light:deep:REM sleep, apnoea hypopnoea index, arousals)
Time frame: 8 weeks
Adherence
Adherence to the prescribed eating window(+/- 1 hour) by smart phone application; includes number of days adherent, length of eating window, 95% eating window
Time frame: 8 weeks
Energy and macronutrient intake
Calculated total energy intake, intake of carbohydrate, protein, fat, saturated fat, fibre, alcohol
Time frame: 8 weeks
Blood pressure
Change in office blood pressure
Time frame: 8 weeks
Body weight
Change in body weight
Time frame: 8 weeks
Appetite sensations
Changes in measures of appetite assessed by validated visual analog scale assessed on a 10 cm scale whereby 0 is very low and 10 is very high.
Time frame: 8 weeks
Gastrointestinal hormones
Change in appetite hormone AUC after each meal and sum of 3 meals (ghrelin, glucagon-like peptide-1 \[GLP-1\])
Time frame: 8 weeks
Documents are hosted by the registry — open the source record to download them.
This study is completed, as verified in May 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Adelaide