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Calories or Time Restriction to Alter Biomarkers of Aging and Diabetes

RECRUITING

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.

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Study details:

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.

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Eligibility criteria

Researchers look for people who fit a certain description, called eligibility criteria. See if you qualify.

Inclusion criteria

Overweight or obesity (BMI 25.1 - 44.9 kg/m2)

Elevated waist circumference (race specific)

Elevated fasting blood glucose (>5.6 mmol/L)

Exclusion criteria

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

obstructive sleep apnea

night eating syndrome

diagnosis or treatment of cancer in the past 3 years (excluding non-melanoma skin cancer)

significant liver or kidney diseases that require ongoing medical care

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

Any autoimmune disease (i.e. rheumatoid arthritis)

Coeliac disease

Score less than 12 of the Australian Diabetes (AUSD) risk assessment tool

Do not eat for a 12 hour window each day for 5 or more days per week

Have extreme or restricted patterns of eating (i.e. following an intermittent fasting diet) or already engage in CR

Other dietary restrictions including vegans, gluten or nut allergies

Night shift-workers (>3 shifts per month)

pregnant, planning a pregnancy or currently breastfeeding

those who have lost or gained >5% of body weight in the last 6 months

donated blood in past 3 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)

do not own, or are not comfortable using, a smart phone and applications

Anti-diabetic medications that lower blood glucose including, but not limited to: SGLT2 inhibitors, metformin, sulfonylureas, glucagon-like peptide-1 (GLP-1) analogues [i.e. semaglutide], thiazolidinediones

affecting weight, appetite or gut motility, including, but not limited to semaglutide, domperidone, cisapride, orlistat, phentermine, topiramate.

Diuretics (i.e. frusemide, thiazides) or combination blood pressure medications containing a diuretic

Beta-blockers

Glucocorticoids

Anti-epileptic medications (i.e. pregabalin and gabapentin)

Tricyclic antidepressants

Some serotonin and norepinephrine reuptake inhibitors (i.e. vortioxetine, mirtazapine and venlafaxine)

Regular use of benzodiazepines or other sleep aids, including melatonin

Antipsychotic medications

Opioid medications unless combined with paracetamol in a single formulation and used occasionally on as needs basis

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Eligibility

Age eligible for study : 35 and older

Healthy volunteers accepted : No

Gender eligible for study: All

Things to know

Study dates

Study start: 2023-03-15

Primary completion: 2025-10-01

Study completion finish: 2025-12-01

Study type

BASIC_SCIENCE

Phase

Trial ID

NCT05769335

Intervention or treatment

OTHER: eCR

OTHER: dCR

OTHER: CR

Conditions

• Obesity

Condition: Obesity
OTHER: eCR and other drugs
Adelaide, South Australia, Australia
Sponsor: University of Adelaide

You may be eligible to participate in this trial based on your search. Check eligibility by answering some questions.

Are you running this trial? If you're a clinic or sponsor, you can claim this study. Claim or learn more.

Find a site

Closest Location:

South Australian Health and Medical Research Institute / The University of Adelaide

Research sites nearby

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South Australian Health and Medical Research Institute / The University of Adelaide
Adelaide, South Australia, Australia

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Participant Group/Arm	Intervention/Treatment
EXPERIMENTAL: early calorie restriction (eCR) 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 Eating time window from 8:00 to 16:00
EXPERIMENTAL: delayed calorie restriction (dCR) 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 Eating time window from 12:00 to 20:00
ACTIVE_COMPARATOR: Calorie restriction (CR) 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 20:00

What is the study measuring?

Primary outcome

Primary Outcome Measure	Primary Outcome Description	Primary Outcome Time Frame
Glucose area under curve (AUC) after 3 meals	Change in glucose AUC after 3 meals	8 weeks

Secondary outcome

Secondary Outcome Measure	Secondary Outcome Description	Secondary Outcome Time Frame
24 h glucose on ward (by continuous glucose monitor (CGM)	Change in 24 h glucose on ward by CGM	8 weeks
Insulin AUCs	Change in insulin AUC after 3 meals	8 weeks
Insulin sensitivity (calculated by Matsuda index where a higher score means greater insulin sensitivity)	Change in insulin sensitivity	8 weeks
Fasting glucose	Change in fasting glucose	8 weeks
Fasting insulin	Change in fasting insulin	8 weeks
C-reactive protein (CRP)	Change in hs-CRP	8 weeks
Body weight	Change in body weight	8 weeks
Physical activity by activity monitor	Change in step count	8 weeks
Adherence to the prescribed eating window (+/- 1 hour) by smart phone application	Adherence to the prescribed eating window(+/- 1 hour) by smart phone application	8 weeks
Change in fat mass	Change in fat mass by bio-electrical impedance analysis	8 weeks

Frequently Asked Questions

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References

Clinical Trials Gov: Calories or Time Restriction to Alter Biomarkers of Aging and Diabetes