Intermittent Fasting for Type 1 Diabetes

Overseen By Krista Varady, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Illinois at Chicago

Must be taking: Insulin, Glucagon

Disqualifiers: T2DM, Eating disorders, Pregnancy, others

Stay on Your Current Meds You can continue your current medications while participating

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 6 months

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores two methods to manage weight and improve blood sugar control in overweight adults with type 1 diabetes. The study compares time-restricted eating (consuming all meals within an 8-hour window) to the usual method of daily calorie restriction. Participants will determine which approach works best for them without daily calorie counting. This trial may suit those managing type 1 diabetes with insulin. As an unphased trial, it offers a unique opportunity to explore innovative diabetes management approaches without the constraints of traditional clinical trial phases.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications. However, since it involves dietary changes and you must be on insulin, it's likely you'll continue your current insulin regimen. It's best to discuss with the trial coordinators or your doctor.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that time-restricted eating (TRE) is generally easy for people to follow. In one study, participants who practiced TRE lost weight and improved their body shape and blood pressure. Importantly, researchers found no major safety issues.

For daily calorie restriction (CR), studies have shown it is safe for weight loss. Research indicates that both intermittent fasting and continuous calorie restriction are safe for people with type 1 diabetes, with no significant safety concerns reported.

Both TRE and CR appear safe and effective for managing weight, with studies finding no major harmful effects. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about exploring intermittent fasting methods like time-restricted eating (TRE) and daily calorie restriction (CR) for managing Type 1 diabetes because these approaches offer a fresh perspective beyond traditional insulin therapy and blood sugar monitoring. Unlike standard treatments that primarily focus on managing insulin levels, these dietary interventions aim to improve metabolic health through lifestyle changes. TRE allows individuals to eat freely within an 8-hour window each day, potentially simplifying meal planning and enhancing adherence. Meanwhile, CR involves reducing daily calorie intake by 25%, which might help improve insulin sensitivity and overall health. These methods could complement existing treatments and offer new ways to manage the condition more naturally.

What evidence suggests that this trial's treatments could be effective for type 1 diabetes?

This trial will compare time-restricted eating (TRE) and daily calorie restriction (CR) for individuals with type 1 diabetes. Research has shown that TRE can aid in weight loss and improve blood sugar levels. In studies with people who have type 2 diabetes, TRE resulted in more weight loss than daily calorie cutting. TRE has also demonstrated benefits for overall health, which can assist in managing type 1 diabetes and obesity.

Daily calorie cutting, known as calorie restriction (CR), is another method that can enhance blood sugar control and aid in weight management. Some studies suggest that reducing calorie intake can lower blood sugar levels and body weight. This trial will study both TRE and CR for their potential benefits for people with type 1 diabetes and obesity. TRE may be easier to follow because it doesn't require daily calorie counting. ^{1 3 4 6 7}

Who Is on the Research Team?

Krista Varady, PhD

Principal Investigator

University of Illinois Chicago

Are You a Good Fit for This Trial?

Adults aged 18-75 with Type 1 Diabetes, a BMI of 25-50, and HbA1c levels between 6.5-9.5% are eligible for this trial if they're on insulin treatment and have been weight stable for the past three months. It's not suitable for those with eating disorders, pregnant women, night shift workers, or individuals with certain severe medical conditions.

Inclusion Criteria

I use insulin multiple times a day or have an insulin pump.

I have type 1 diabetes and am using insulin.

Your HbA1c level is between 6.5% and 9.5% regardless of the medications you're taking.

Exclusion Criteria

Pregnant, or trying to become pregnant

People who work at night are not eligible.

I do not have heart failure, severe lung, liver, kidney diseases, active cancer, or a history of stroke.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants are assigned to either time restricted eating (TRE) or daily calorie restriction (CR) for weight management and glycemic control

6 months

Monthly visits (in-person or virtual)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Daily calorie restriction
• Time restricted eating

Trial Overview The study is testing two dietary approaches to manage weight and improve blood sugar control in adults with obesity and Type 1 Diabetes: Time Restricted Eating (TRE), which limits food intake to a specific time window each day versus Daily Calorie Restriction (CR), where calorie intake is monitored daily.

How Is the Trial Designed?

Group I: Time restricted eating (TRE) Experimental Treatment 1 Intervention

8-h eating window Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)

Group II: Daily calorie restriction (CR) Experimental Treatment 1 Intervention

25% energy restriction every day Diet counseling provided

Group III: Control Active Control 1 Intervention

Ad libitum food intake, eating over more than 10 hours per day

Who Is Running the Clinical Trial?

University of Illinois at Chicago

Lead Sponsor

Trials

653

Recruited

1,574,000+

Published Research Related to This Trial

Intermittent fasting (IF) showed similar reductions in HbA1C and BMI compared to continuous energy restriction in individuals with Type 2 Diabetes Mellitus, but these differences were not statistically significant.

The review highlights the need for more extensive research on IF as a treatment for T2DM, as current evidence is insufficient to influence clinical guidelines despite its potential benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Review of Intermittent Fasting as a Treatment for Type 2 Diabetes Mellitus. Silver, DT., Pekari, TB.[2023]

A novel intermittent fasting approach called iTRE, which involves eating during a specific time window, showed greater improvements in glucose tolerance compared to traditional calorie restriction (CR) after 6 months in a study of 209 adults at risk for type 2 diabetes.

While iTRE led to better glucose metabolism initially, these benefits diminished by the 18-month follow-up, and participants reported more fatigue and some mild adverse effects compared to those on CR or standard care.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent fasting plus early time-restricted eating versus calorie restriction and standard care in adults at risk of type 2 diabetes: a randomized controlled trial. Teong, XT., Liu, K., Vincent, AD., et al.[2023]

Intermittent fasting (IF) shows potential benefits for diabetic patients, with evidence suggesting that its positive effects may outweigh the risks, based on various studies including animal research and small clinical trials.

However, there is currently insufficient high-quality evidence to recommend IF as a standard treatment for diabetes, highlighting the need for more rigorous long-term studies to determine the safest and most effective IF regimens.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evidence-based information about intermittent fasting in diabetes patients: useful or harmful? Altay, M.[2023]

In a 12-week study involving 23 obese adults, time-restricted feeding (TRF) with an 8-hour eating window was found to be safe, as there were no significant changes in self-reported adverse events or disordered eating patterns.

The study suggests that TRF can effectively support weight loss in obese individuals without negatively impacting their health or body image perception.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of 8-h time restricted feeding in adults with obesity. Gabel, K., Hoddy, KK., Varady, KA.[2019]

Intermittent fasting (IF) and continuous energy-restricted diets (CERD) showed similar effects on glycemic control in patients with type 2 diabetes and metabolic syndrome, based on a meta-analysis of four studies with 355 participants.

However, IF resulted in greater weight loss compared to CERD, indicating it may be a beneficial dietary approach for overweight or obese patients with these conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent fasting versus continuous energy-restricted diet for patients with type 2 diabetes mellitus and metabolic syndrome for glycemic control: A systematic review and meta-analysis of randomized controlled trials. Wang, X., Li, Q., Liu, Y., et al.[2021]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6566372/

Carbohydrate Restriction in Type 1 Diabetes: A Realistic ... There are reports that very low carbohydrate diets (VLCD), defined as 20–50 g of carbohydrate per day [28], can lead to reductions of HbA1c as low as 5.3% in ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8668312/

Comparing the Efficacy and Safety of Low-Carbohydrate Diets ... We found that treatment with LCDs achieved more effective improvements in glycemic and body weight control, as well as the concentrations of TG ...

3. frontiersin.org frontiersin.org/journals/physiology/articles/10.3389/fphys.2025.1629751/full

Calorie and time-restricted feeding improves liver ... Calorie restriction (CR) and time-restricted feeding (TRF) have shown beneficial effects in several metabolic disorders, especially in obesity ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S2589537025001543

Effects of different dietary patterns on glucose management ... Evidence rated with moderate certainty suggests that higher-fiber and carbohydrate-restricted diets have beneficial effects on glycemic control in individuals ...

5. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2811116

Effect of Time-Restricted Eating on Weight Loss in Adults ... In a 6-month randomized clinical trial involving 75 adults with T2D, TRE was more effective for weight loss (−3.6%) than CR (−1.8%) compared with controls.

6. sciencedirect.com sciencedirect.com/science/article/abs/pii/S2451847618300290

The safety and efficacy of weight loss via intermittent ... These findings suggest that both intermittent fasting or continuous energy restriction are safe and effective weight loss approaches for people with type 1 ...

7. dmsjournal.biomedcentral.com dmsjournal.biomedcentral.com/articles/10.1186/s13098-024-01492-9

The effect of different dietary restriction on weight ... The current evidence supports the conclusion that both IF and CER have beneficial effects on weight management and metabolic parameter ...