Diabetes Mellitus, Type 2NCT06118931
Time-restricted Eating, Window Timing, Type 2 Diabetes Status and Sex on Glycemic Control
A study testing Early (7:00 - 16:00) TRE, Mid (9:30 - 18:30) TRE and Late (12:00 - 21:00) TRE in people with Diabetes Mellitus, Type 2 and Obesity, run by University of Toronto at 1 site in Canada.
Trial summary
This study will evaluate the effectiveness of time-restricted eating (TRE), which is a form of intermittent fasting. When performing TRE, individuals consume all of their calories within a specific time window and then only consume water or other no calorie drinks the rest of the day. TRE is performed each day. Read more about this study
- Who is it for?
- Ages 40 years and older
- Conditions the study is for
- Diabetes Mellitus, Type 2, Obesity, Prediabetic State
- What is being tested?
- Early (7:00 - 16:00) TRE, Mid (9:30 - 18:30) TRE and Late (12:00 - 21:00) TRE
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 123 participants
- Where
- 1 siteCanada
- Study dates
- 28 Jun 2025to 28 Jun 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 40 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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:
- History of or referral for bariatric surgery
- Weight loss >3% in the last 3 months
- Taking antiobesity (weight loss) medications
- Body weight >390lbs
Show all 12Show fewer
- Diagnosed with severe cognitive disorder that precludes them from giving consent
- Inability or unwillingness to change their eating window to follow those prescribed in the study
- Currently consistently eating during <11.5 hour period .
- Physician-diagnosed eating disorder
- Having a pacemaker or receiving dialysis.
- Not having access to a Lifelabs location.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Teresita Gormaz Clinical Trial coordinator, MsC contact
Canada1 site, 1 recruiting
- Recruiting
Remote Ontario-wide
Toronto, Ontario
Amy A Kirkham, PhD
Amy A Kirkham, PhD
About this study
Official title: The Impact of Time-restricted Eating, Window Timing, Type 2 Diabetes Status and Sex on Glycemic Control
This study will evaluate the effectiveness of time-restricted eating (TRE), which is a form of intermittent fasting. When performing TRE, individuals consume all of their calories within a specific time window and then only consume water or other no calorie drinks the rest of the day. TRE is performed each day. There is no restriction on the quality or amount of food that people can consume during their eating window (ad libitum eating) with TRE, which can last anywhere from 4 to 12 hours. We are comparing three different 9-hour eating windows to determine whether the start and stop time of the eating window impact blood sugar control in individuals with obesity who also have or are at risk for type 2 diabetes. We also aim to determine if there are differences in the effects of the timing of eating window between males and females.
Read the detailed description
The overarching aim of this study is to evaluate the interactions between TRE window timing, type 2 diabetes status, and sex among individuals with obesity. The first objective is to compare the effects of three 9-h TRE window times (early: 7:00-16:00 h, mid: 9:30-18:30 h, delayed: 12:00-21:00 h) on real-time, free-living glycemic control. The second objective is to determine if type 2 diabetes status (type 2 diabetes versus prediabetes or moderate+ risk for type 2 diabetes aka at risk for type 2 diabetes) modifies the effect of eating window timing on glycemic control outcomes. The exploratory objectives include: 1) determine whether sex modifies TRE adherence or the effect of TRE on metabolic changes relative to control; and 2) to compare changes in dietary intake, body weight, and blood pressure within and between early, mid, and delayed TRE. We have the following hypotheses related to these objectives:
- The early TRE window will result in the most favourable glycemic control outcomes but also the lowest participant acceptability followed by mid and delayed TRE.
- There will be larger differences in glycemic control outcomes between the TRE window timings among those with type 2 diabetes compared to those at risk for type 2 diabetes.
- TRE adherence and changes in glycemic control, and weight loss with all TRE window times (relative to control) will be higher in men vs women.
- Energy, carbohydrate, and sugar intake, body weight, and blood pressure will decrease during TRE, but with no differences by window timing.
- Conditions
- Diabetes Mellitus, Type 2, Obesity, Prediabetic State, Hyperglycemia
- Being tested
- Early (7:00 - 16:00) TRE, Mid (9:30 - 18:30) TRE, Late (12:00 - 21:00) TRE
- Keywords
- Time-restricted eating, Type 2 Diabetes, Obesity, Glycemic Control
- Medical subject headings
- Diabetes Mellitus, Type 2, Obesity, Prediabetic State, Hyperglycemia, Intermittent Fasting
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Early (7:00 - 16:00) TREBehavioural
A standardized TRE Protocol where participants eat ad libitum between the hours of 7:00 to 16:00 for 7 days. On the 8th day, they will consume a meal replacement beverage at 7:00, and not consume anything else for two hours.
Mid (9:30 - 18:30) TREBehavioural
A standardized TRE Protocol where participants eat ad libitum between the hours of 9:30 to 18:30 for 7 days. On the 8th day, they will consume a meal replacement beverage at 9:30, and not consume anything else for two hours.
Late (12:00 - 21:00) TREBehavioural
A standardized TRE Protocol where participants eat ad libitum between the hours of 12:00 to 21:00 for 7 days. On the 8th day, they will consume a meal replacement beverage at 12:00, and not consume anything else for two hours.
| Study group | Role | What they receive |
|---|---|---|
| Early (7:00-16:00h) TRE | Experimental | Participants will be asked to eat ad libitum between the hours of 7:00 - 16:00 each day for seven days, and then only drink water or other no calorie beverages for the rest of the day. On the 8th day, they will consume one meal replacement beverage at 7:00 and be instructed to not consume anything else for two hours. After the two hours they will be instructed to return to their normal baseline eating habits. Receives: Behavioral: Early (7:00 - 16:00) TRE |
| Mid (9:30-18:30h) TRE | Experimental | Participants will be asked to eat ad libitum between the hours of 9:30 - 18:30 each day for seven days, and then only drink water or other no calorie beverages for the rest of the day. On the 8th day, they will consume one meal replacement beverage at 9:30 and be instructed to not consume anything else for two hours. After the two hours they will be instructed to return to their normal baseline eating habits. Receives: Behavioral: Mid (9:30 - 18:30) TRE |
| Late (12:00-21:00h) TRE | Experimental | Participants will be asked to eat ad libitum between the hours of 12:00 - 21:00 each day for seven days, and then only drink water or other no calorie beverages for the rest of the day. On the 8th day, they will consume one meal replacement beverage at 12:00 and be instructed to not consume anything else for two hours. After the two hours they will be instructed to return to their normal baseline eating habits. Receives: Behavioral: Late (12:00 - 21:00) TRE |
| Control | No intervention | During the first week of the study, participants will be asked to eat as they normally do, and to not make any changes regarding when they are stopping or starting eating. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Average 24-hour glucose total area under the curve (AUC) over 7 days
Assessed for 7 continuous days using a continuous glucose monitor.
Measured: 7 days
Secondary outcomes (8)
Average 24-hour glucose over 7 days
Assessed for 7 continuous days using a continuous glucose monitor.
Measured: 7 days
Average daily nocturnal glucose over 7 evenings
Assessed for 7 continuous evenings based on the sleep period identified by the Fitbit tracker using a continuous glucose monitor.
Measured: 7 days
Average daily time spent in hyperglycemia over 7 days
The average number of hours with glucose >10 mmol/L over 7 continuous days assessed with a continuous glucose monitor.
Measured: 7 days
Postprandial glucose
Assessed on the morning after the 7th day of each TRE protocol. Participants will consume a standardized breakfast at a specified time, and glucose will be evaluated via continuous glucose monitor from the time they start consuming the breakfast for 2 hours.
Measured: 2 hours
Glycemic viability
The average of each standard metrics of glycemic viability (standard deviation, coefficient of variation, mean amplitude of glycemic exercise, and continuous overall net glycemic action) will be calculated over 7 continuous days from continuous glucose monitors.
Measured: 7 days
Patient acceptability
Patient acceptability will be assessed based on researcher-developed questions related to their experience with each TRE protocol.
Measured: 7 days
TRE fasting duration adherence
Participants will receive twice daily text messages asking what time they started and stopped eating that day, which will be used to calculate the length of the fast each day. Adherence will be calculated as the % of days where the participant fasted for 15h or longer.
Measured: 7 days
TRE fasting window adherence
The proportion of days where participants began and ended their meal within 15 min or 30 min of their prescribed time.
Measured: 7 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Nov 2023
- Study start28 Jun 2025
- Primary completion28 Jun 2027 (estimated)
- Study completion28 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Diabetes Mellitus, Type 2Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 123 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Toronto
- Sponsor type
- University, hospital or other
- Collaborators
- Diabetes Canada, Wharton Medical Clinic
- Responsible party
- Principal investigator, Amy Kirkham, University of Toronto
- Investigators
- Amy A. Kirkham, PhD, Principal investigator, University of Toronto
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06118931
- Sponsor's protocol ID
- 44122
- Status last verified
- Sep 2025
- First submitted
- 31 Oct 2023
- Last updated
- 30 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 30 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Time-restricted Eating, Window Timing, Type 2 Diabetes Status and Sex on Glycemic Control
- ClinicalTrials.gov ID
- NCT06118931
- Acronym / sponsor ID
- 44122
- Conditions
- Diabetes Mellitus, Type 2, Obesity, Prediabetic State, Hyperglycemia
- Keywords
- Time-restricted eating, Type 2 Diabetes, Obesity, Glycemic Control
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 123 participants (estimated)
- Lead sponsor
- University of TorontoUniversity, hospital or other
- Collaborators
- Diabetes Canada, Wharton Medical Clinic
- Study start
- 28 Jun 2025 (actual)
- Primary completion
- 28 Jun 2027 (estimated)
- Study completion
- 28 Jun 2027 (estimated)
- First posted
- 7 Nov 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the effectiveness of time-restricted eating (TRE), which is a form of intermittent fasting. When performing TRE, individuals consume all of their calories within a specific time window and then only consume water or other no calorie drinks the rest of the day. TRE is performed each day. There is no restriction on the quality or amount of food that people can consume during their eating window (ad libitum eating) with TRE, which can last anywhere from 4 to 12 hours. We are comparing three different 9-hour eating windows to determine whether the start and stop time of the eating window impact blood sugar control in individuals with obesity who also have or are at risk for type 2 diabetes. We also aim to determine if there are differences in the effects of the timing of eating window between males and females.
Detailed description
The overarching aim of this study is to evaluate the interactions between TRE window timing, type 2 diabetes status, and sex among individuals with obesity. The first objective is to compare the effects of three 9-h TRE window times (early: 7:00-16:00 h, mid: 9:30-18:30 h, delayed: 12:00-21:00 h) on real-time, free-living glycemic control. The second objective is to determine if type 2 diabetes status (type 2 diabetes versus prediabetes or moderate+ risk for type 2 diabetes aka at risk for type 2 diabetes) modifies the effect of eating window timing on glycemic control outcomes. The exploratory objectives include: 1) determine whether sex modifies TRE adherence or the effect of TRE on metabolic changes relative to control; and 2) to compare changes in dietary intake, body weight, and blood pressure within and between early, mid, and delayed TRE. We have the following hypotheses related to these objectives:
- The early TRE window will result in the most favourable glycemic control outcomes but also the lowest participant acceptability followed by mid and delayed TRE.
- There will be larger differences in glycemic control outcomes between the TRE window timings among those with type 2 diabetes compared to those at risk for type 2 diabetes.
- TRE adherence and changes in glycemic control, and weight loss with all TRE window times (relative to control) will be higher in men vs women.
- Energy, carbohydrate, and sugar intake, body weight, and blood pressure will decrease during TRE, but with no differences by window timing.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Early (7:00-16:00h) TRE | Experimental | Behavioral: Early (7:00 - 16:00) TREParticipants will be asked to eat ad libitum between the hours of 7:00 - 16:00 each day for seven days, and then only drink water or other no calorie beverages for the rest of the day. On the 8th day, they will consume one meal replacement beverage at 7:00 and be instructed to not consume anything else for two hours. After the two hours they will be instructed to return to their normal baseline eating habits. |
| Mid (9:30-18:30h) TRE | Experimental | Behavioral: Mid (9:30 - 18:30) TREParticipants will be asked to eat ad libitum between the hours of 9:30 - 18:30 each day for seven days, and then only drink water or other no calorie beverages for the rest of the day. On the 8th day, they will consume one meal replacement beverage at 9:30 and be instructed to not consume anything else for two hours. After the two hours they will be instructed to return to their normal baseline eating habits. |
| Late (12:00-21:00h) TRE | Experimental | Behavioral: Late (12:00 - 21:00) TREParticipants will be asked to eat ad libitum between the hours of 12:00 - 21:00 each day for seven days, and then only drink water or other no calorie beverages for the rest of the day. On the 8th day, they will consume one meal replacement beverage at 12:00 and be instructed to not consume anything else for two hours. After the two hours they will be instructed to return to their normal baseline eating habits. |
| Control | No intervention | –During the first week of the study, participants will be asked to eat as they normally do, and to not make any changes regarding when they are stopping or starting eating. |
Who may qualify
- Ages
- 40 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (12 listed)
- 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:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Early (7:00 - 16:00) TREA standardized TRE Protocol where participants eat ad libitum between the hours of 7:00 to 16:00 for 7 days. On the 8th day, they will consume a meal replacement beverage at 7:00, and not consume anything else for two hours. | Behavioural | Early (7:00-16:00h) TRE |
| Mid (9:30 - 18:30) TREA standardized TRE Protocol where participants eat ad libitum between the hours of 9:30 to 18:30 for 7 days. On the 8th day, they will consume a meal replacement beverage at 9:30, and not consume anything else for two hours. | Behavioural | Mid (9:30-18:30h) TRE |
| Late (12:00 - 21:00) TREA standardized TRE Protocol where participants eat ad libitum between the hours of 12:00 to 21:00 for 7 days. On the 8th day, they will consume a meal replacement beverage at 12:00, and not consume anything else for two hours. | Behavioural | Late (12:00-21:00h) TRE |
Primary outcome
Average 24-hour glucose total area under the curve (AUC) over 7 days
Time frame: 7 days
Assessed for 7 continuous days using a continuous glucose monitor.
8 secondary outcomes
Average 24-hour glucose over 7 days
Time frame: 7 days
Average daily nocturnal glucose over 7 evenings
Time frame: 7 days
Average daily time spent in hyperglycemia over 7 days
Time frame: 7 days
Postprandial glucose
Time frame: 2 hours
Glycemic viability
Time frame: 7 days
Patient acceptability
Time frame: 7 days
TRE fasting duration adherence
Time frame: 7 days
TRE fasting window adherence
Time frame: 7 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jun 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Teresita Gormaz Clinical Trial coordinator, MsC contact
Amy A. Kirkham, PhD principal investigator
University of Toronto
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Early (7:00 - 16:00) TRE, Mid (9:30 - 18:30) TRE and Late (12:00 - 21:00) TRE in people with Diabetes Mellitus, Type 2 and Obesity, run by University of Toronto at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Amy A Kirkham, PhD (416-946-4069, amy.kirkham@utoronto.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Average 24-hour glucose total area under the curve (AUC) over 7 days (time frame: 7 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jun 2026.