Type 1 DiabetesNCT06134986
Intermittent Fasting in Adults With Type 1 Diabetes
A study testing Time restricted eating and Daily calorie restriction in people with Type 1 Diabetes and Obesity, run by University of Illinois Chicago at 1 site in United States.
Trial summary
The majority of adults with type 1 diabetes (T1DM) have either overweight or obesity. As such, dietary management has been recommended as an adjunct to insulin treatment to improve glycemic control and facilitate weight loss in patients with T1DM. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Type 1 Diabetes, Obesity
- What is being tested?
- Time restricted eating and Daily calorie restriction
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 32 participants
- Where
- 1 siteUnited States
- Study dates
- 20 Nov 2023to 1 Sep 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Previously diagnosed with T1DM and currently using insulin
- HbA1c: 6.5-9.5% (regardless of medication use)
- Age between 18 to 75 years old
- BMI between 25 and 50 kg/m2
- Independently living (i.e., subjects who do not live in a nursing home or institution)
- On either multiple daily doses of insulin injections (MDII) or using an insulin pump (with or without closed loop feature)
- Active prescription for daily use of a continous glucose monitor (CGM) or willing to be provided with a CGM during the study (at no cost)
- Active prescription for glucagon
Who cannot join
- History of severe hypoglycemia defined as requiring help from others, needed to use emergency glucagon administration in the past 6 months.
- Medical history of heart failure, unstable coronary artery disease, chronic obstructive pulmonary disease, requiring oxygen, cirrhosis, active cancer, history of stroke, cognitive impairment, end stage renal disease (eGFR ≤30 ml/min/m2)
- Previously diagnosed with T2DM
- Have a history of eating disorders (anorexia, bulimia, or binge eating disorder)
- Are not weight stable for 3 months prior to the beginning of study (weight gain or loss > 4%)
- Are not able to keep a food diary for 7 consecutive days during screening
Show all 11Show fewer
- Are taking certain drugs that have significant weight loss outcomes (weight loss medications, specifically GLP1 agonist, GLP-1/GIP agonists)
- Are eating less than a 10-hour window at baseline
- Are perimenopausal (menses does not appear every 27-32d)
- Are pregnant, or trying to become pregnant
- Are night shift workers
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Illinois Chicago
Chicago, Illinois, 60612
About this study
The majority of adults with type 1 diabetes (T1DM) have either overweight or obesity. As such, dietary management has been recommended as an adjunct to insulin treatment to improve glycemic control and facilitate weight loss in patients with T1DM. Daily calorie restriction (CR) is the main diet prescribed to patients with T1DM for weight loss. However, many patients find it difficult to adhere to CR because calorie intake must be vigilantly monitored every day. In light of these problems with CR, another approach that limits timing of food intake, instead of number of calories consumed, has been developed. This diet is called "time restricted eating" (TRE) and involves confining the period of food intake to 6-8 h per day. TRE allows individuals to self-select foods and eat ad libitum during a large part of the day, which greatly increases compliance to these protocols. The simplicity of TRE, its accommodation of dietary preferences, and associated weight loss may translate to improved glycemic measures in patients with T1DM. The present study will be the first randomized controlled trial to compare the effect of TRE versus CR for weight management and improved glycemic control in adults with obesity and T1DM.
- Conditions
- Type 1 Diabetes, Obesity
- Being tested
- Time restricted eating, Daily calorie restriction
- Medical subject headings
- Diabetes Mellitus, Type 1, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Time restricted eatingOther
8-h eating window Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)
Daily calorie restrictionOther
25% energy restriction every day Diet counseling provided
| Study group | Role | What they receive |
|---|---|---|
| Time restricted eating (TRE) | Experimental | 8-h eating window Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast) Receives: Other: Time restricted eating |
| Daily calorie restriction (CR) | Experimental | 25% energy restriction every day Diet counseling provided Receives: Other: Daily calorie restriction |
| Control | No intervention | Ad libitum food intake, eating over more than 10 hours per day |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in percent body weight
Measured by an electronic scale
Measured: Measured at baseline and month 6
Secondary outcomes (17)
Change in HbA1c
Measured by ELISA
Measured: Measured at baseline and month 6
Change in total time in euglycemic range
Measured by continuous glucose monitor (CGM)
Measured: Measured at baseline and month 6
Change in mean glucose level
Measured by continuous glucose monitor (CGM)
Measured: Measured at baseline and month 6
Change in standard deviation of glucose level
Measured by continuous glucose monitor (CGM)
Measured: Measured at baseline and month 6
Change in coefficient of variation of glucose level
Measured by continuous glucose monitor (CGM)
Measured: Measured at baseline and month 6
Change in absolute body weight
Measured by an electronic scale
Measured: Measured at baseline and month 6
Change in fat mass, lean mass, visceral fat mass
Measured by DXA
Measured: Measured at baseline and month 6
Change in waist circumference
Measured by measuring tape
Measured: Measured at baseline and month 6
Change in body mass index (BMI)
Calculated as kg/meter squared
Measured: Measured at baseline and month 6
Change in plasma lipids (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides)
Measured using enzymatic kits, standardized reagents, and standardsand analyzed using a microplate reader
Measured: Measured at baseline and month 6
Change in systolic and diastolic blood pressure
Measured by blood pressure cuff
Measured: Measured at baseline and month 6
Change in heart rate
Measured by blood pressure cuff
Measured: Measured at baseline and month 6
Change in energy and nutrient intake
Measured by 7-day food record
Measured: Measured at baseline and month 6
Change in dietary adherence
Measured by 7-day food record and adherence log
Measured: Measured at baseline and month 6
Change in physical activity (steps/d)
Measured by activity monitor
Measured: Measured at baseline and month 6
Adverse events
Measured by adverse events survey and continous glucose monitor (for events of hypoglycemia and hyperglycemia)
Measured: Measured at baseline and month 6
Change in insulin dose
Measured by recording total insulin dose, basal insulin dose, and bolus insulin dose
Measured: Measured at baseline and month 6
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Nov 2023
- Study start20 Nov 2023
- Primary completion1 Sep 2025
- Study completion1 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Type 1 DiabetesStudies of the same condition, open and under way.
- More trials run by University of Illinois ChicagoThe sponsor's other registered studies.
- 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
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 32 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Illinois Chicago
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Krista Varady, University of Illinois Chicago
- Investigators
- Krista Varady, PhD, Principal investigator, University of Illinois Chicago
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06134986
- Sponsor's protocol ID
- 2023-0678
- Status last verified
- Feb 2026
- First submitted
- 11 Nov 2023
- Last updated
- 2 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Intermittent Fasting in Adults With Type 1 Diabetes
- ClinicalTrials.gov ID
- NCT06134986
- Acronym / sponsor ID
- 2023-0678
- Conditions
- Type 1 Diabetes, Obesity
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 32 participants (actual)
- Lead sponsor
- University of Illinois ChicagoUniversity, hospital or other
- Study start
- 20 Nov 2023 (actual)
- Primary completion
- 1 Sep 2025 (actual)
- Study completion
- 1 Sep 2025 (actual)
- First posted
- 18 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.
The majority of adults with type 1 diabetes (T1DM) have either overweight or obesity. As such, dietary management has been recommended as an adjunct to insulin treatment to improve glycemic control and facilitate weight loss in patients with T1DM. Daily calorie restriction (CR) is the main diet prescribed to patients with T1DM for weight loss. However, many patients find it difficult to adhere to CR because calorie intake must be vigilantly monitored every day. In light of these problems with CR, another approach that limits timing of food intake, instead of number of calories consumed, has been developed. This diet is called "time restricted eating" (TRE) and involves confining the period of food intake to 6-8 h per day. TRE allows individuals to self-select foods and eat ad libitum during a large part of the day, which greatly increases compliance to these protocols. The simplicity of TRE, its accommodation of dietary preferences, and associated weight loss may translate to improved glycemic measures in patients with T1DM. The present study will be the first randomized controlled trial to compare the effect of TRE versus CR for weight management and improved glycemic control in adults with obesity and T1DM.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Time restricted eating (TRE) | Experimental | Other: Time restricted eating8-h eating window Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast) |
| Daily calorie restriction (CR) | Experimental | Other: Daily calorie restriction25% energy restriction every day Diet counseling provided |
| Control | No intervention | –Ad libitum food intake, eating over more than 10 hours per day |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Previously diagnosed with T1DM and currently using insulin
- HbA1c: 6.5-9.5% (regardless of medication use)
- Age between 18 to 75 years old
- BMI between 25 and 50 kg/m2
- Independently living (i.e., subjects who do not live in a nursing home or institution)
Key exclusion criteria (11 listed)
- History of severe hypoglycemia defined as requiring help from others, needed to use emergency glucagon administration in the past 6 months.
- Medical history of heart failure, unstable coronary artery disease, chronic obstructive pulmonary disease, requiring oxygen, cirrhosis, active cancer, history of stroke, cognitive impairment, end stage renal disease (eGFR ≤30 ml/min/m2)
- Previously diagnosed with T2DM
- Have a history of eating disorders (anorexia, bulimia, or binge eating disorder)
- Are not weight stable for 3 months prior to the beginning of study (weight gain or loss > 4%)
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 |
|---|---|---|
| Time restricted eating8-h eating window Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast) | Other | Time restricted eating (TRE) |
| Daily calorie restriction25% energy restriction every day Diet counseling provided | Other | Daily calorie restriction (CR) |
Primary outcome
Change in percent body weight
Time frame: Measured at baseline and month 6
Measured by an electronic scale
17 secondary outcomes
Change in HbA1c
Time frame: Measured at baseline and month 6
Change in total time in euglycemic range
Time frame: Measured at baseline and month 6
Change in mean glucose level
Time frame: Measured at baseline and month 6
Change in standard deviation of glucose level
Time frame: Measured at baseline and month 6
Change in coefficient of variation of glucose level
Time frame: Measured at baseline and month 6
Change in absolute body weight
Time frame: Measured at baseline and month 6
Change in fat mass, lean mass, visceral fat mass
Time frame: Measured at baseline and month 6
Change in waist circumference
Time frame: Measured at baseline and month 6
Change in body mass index (BMI)
Time frame: Measured at baseline and month 6
Change in plasma lipids (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides)
Time frame: Measured at baseline and month 6
Change in systolic and diastolic blood pressure
Time frame: Measured at baseline and month 6
Change in heart rate
Time frame: Measured at baseline and month 6
Change in energy and nutrient intake
Time frame: Measured at baseline and month 6
Change in dietary adherence
Time frame: Measured at baseline and month 6
Change in physical activity (steps/d)
Time frame: Measured at baseline and month 6
Adverse events
Time frame: Measured at baseline and month 6
Change in insulin dose
Time frame: Measured at baseline and month 6
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Mar 2026.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
Krista Varady, PhD principal investigator
University of Illinois Chicago
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Time restricted eating and Daily calorie restriction in people with Type 1 Diabetes and Obesity, run by University of Illinois Chicago at 1 site in United States.
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 8 inclusion and 11 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: finished, as of the sponsor's last update on 2 Mar 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 United States. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in percent body weight (time frame: Measured at baseline and month 6). 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 2 Mar 2026.