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Clinical trial Recruiting at 1 site Interventional Ages 40 and up

Eating window timing to improve blood sugar in adults with obesity and type 2 diabetes or at risk

Official title: The Impact of Time-restricted Eating, Window Timing, Type 2 Diabetes Status and Sex on Glycemic Control

Run by University of Toronto · NCT06118931 · Data updated 2026-11-12

This study tests whether eating only during one of three nine-hour daily windows can improve blood sugar control in adults with obesity who have or are at risk for type 2 diabetes.

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Quick facts

Study typeInterventional
Ages40 Years and up
SexAll
Enrollment123 (estimated)
SponsorUniversity of Toronto
Academic / other
Locations1 site (Toronto, Ontario)
StatusRecruiting
StartedJune 28, 2025
Main results expectedJune 28, 2027
Study endsJune 28, 2027
Registry record updatedJune 30, 2026
Trial IDNCT06118931 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adults over 18 with BMI 30–50 kg/m2 who have type 2 diabetes (within the study's medication and A1c limits) or are at high risk for diabetes, own a Bluetooth-capable smartphone, and are willing to restrict eating to a prescribed nine-hour window are ideal candidates.

Probably not a fit

People who use insulin or sulfonylureas, have recent major weight loss or bariatric surgery, take prescription weight-loss drugs, cannot change their eating window, exceed the study's weight limits, or live outside Ontario are unlikely to benefit or be eligible.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Adults with obesity and either diagnosed type 2 diabetes (meeting the study medication and A1c limits) or at high risk for diabetes will be assigned to one of three nine-hour time-restricted eating (TRE) windows: early (7:00–16:00), mid (9:30–18:30), or late (12:00–21:00), and followed remotely across Ontario. Participants will eat ad libitum within their assigned window each day while wearing continuous glucose monitors and using smartphone-connected devices to capture real-time, free-living glycemic data. The trial will compare glycemic control between windows, test whether effects differ by diabetes status, and explore sex differences in adherence and metabolic responses. Secondary outcomes include changes in dietary intake, body weight, and blood pressure.

Why it matters

Potential benefit: If successful, the results could identify which daily eating window best improves blood sugar and help tailor simple meal-timing guidance for people with obesity and diabetes or prediabetes.

How similar studies have gone: Previous small TRE trials, especially with early windows, have shown mixed but promising improvements in glucose control and weight, though head-to-head comparisons of different window timings are limited.

Who can join: the full rules

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Aged 40 years or older
* Body mass index \<50 kg/m2
* Have access to an Apple or Android cellphone with Bluetooth.
* Have type 2 diabetes or be at risk for type 2 diabetes (defined as self-report of pre-diabetes, a recent (within 12 months) measure of HbA1c between 5.7 and 6.4%, waist circumference (WC) that is BMI specific; for women: BMI \>= 18.5-24.9, WC \>= 80cm; BMI \>= 25-29.9, WC \>= 90cm; BMI \>= 30-34.9, WC \>= 105cm; BMI \>= 35+, WC \>= 115cm; for men: BMI \>= 18.5-24.9, WC \>= 90cm; BMI \>= 25-29.9, WC \>= 100cm; BMI \>= 30-34.9, WC \>= 110cm; BMI \>= 35+, WC \>= 125cm.

Exclusion Criteria:

* Individuals with type 2 diabetes will be excluded if: (1) currently on \>2 monotherapies for diabetes, (2) have had diabetes therapy medication or dosage changes \<3 months, (3) self-reported hemoglobin A1c \>9.0%, (4) taking exogenous insulin, or (5) taking sulfonylureas
* The following exclusion criteria applies to all potential participants:

  1. History of or referral for bariatric surgery
  2. Weight loss \>3% in the last 3 months
  3. Taking antiobesity (weight loss) medications
  4. Body weight \>390lbs
  5. Diagnosed with severe cognitive disorder that precludes them from giving consent
  6. Inability or unwillingness to change their eating window to follow those prescribed in the study
  7. Currently consistently eating during \<11.5 hour period .
  8. Physician-diagnosed eating disorder
  9. Having a pacemaker or receiving dialysis.
  10. Not having access to a Lifelabs location.

Where it's running

  • Remote Ontario-wide
    Toronto, Ontario, Canada     Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov ↗ Find more trials like this →
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Diabetes Mellitus, Type 2 185Obesity 1426Prediabetic State 17Hyperglycemia 54University of Toronto 45
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.