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Completed

NCT Number: NCT06134986

Intermittent Fasting in Adults With Type 1 Diabetes

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.

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Key information

Conditions

Type 1 Diabetes Autoimmune Diseases Body Weight Diabetes Mellitus Diabetes Mellitus, Type 1 Endocrine System Diseases Glucose Metabolism Disorders Immune System Diseases Metabolic Diseases Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Illinois Chicago

Chicago, Illinois, 60612, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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
  • 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

Treatment and study plan

Time restricted eating

Other

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 restriction

Other

25% energy restriction every day Diet counseling provided

Primary outcomes

  1. Change in percent body weight

    Time frame: Measured at baseline and month 6

    Measured by an electronic scale

Secondary outcomes

  1. Change in HbA1c

    Time frame: Measured at baseline and month 6

    Measured by ELISA

  2. Change in total time in euglycemic range

    Time frame: Measured at baseline and month 6

    Measured by continuous glucose monitor (CGM)

  3. Change in mean glucose level

    Time frame: Measured at baseline and month 6

    Measured by continuous glucose monitor (CGM)

  4. Change in standard deviation of glucose level

    Time frame: Measured at baseline and month 6

    Measured by continuous glucose monitor (CGM)

  5. Change in coefficient of variation of glucose level

    Time frame: Measured at baseline and month 6

    Measured by continuous glucose monitor (CGM)

  6. Change in absolute body weight

    Time frame: Measured at baseline and month 6

    Measured by an electronic scale

  7. Change in fat mass, lean mass, visceral fat mass

    Time frame: Measured at baseline and month 6

    Measured by DXA

  8. Change in waist circumference

    Time frame: Measured at baseline and month 6

    Measured by measuring tape

  9. Change in body mass index (BMI)

    Time frame: Measured at baseline and month 6

    Calculated as kg/meter squared

  10. Change in plasma lipids (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides)

    Time frame: Measured at baseline and month 6

    Measured using enzymatic kits, standardized reagents, and standardsand analyzed using a microplate reader

  11. Change in systolic and diastolic blood pressure

    Time frame: Measured at baseline and month 6

    Measured by blood pressure cuff

  12. Change in heart rate

    Time frame: Measured at baseline and month 6

    Measured by blood pressure cuff

  13. Change in energy and nutrient intake

    Time frame: Measured at baseline and month 6

    Measured by 7-day food record

  14. Change in dietary adherence

    Time frame: Measured at baseline and month 6

    Measured by 7-day food record and adherence log

  15. Change in physical activity (steps/d)

    Time frame: Measured at baseline and month 6

    Measured by activity monitor

  16. Adverse events

    Time frame: Measured at baseline and month 6

    Measured by adverse events survey and continous glucose monitor (for events of hypoglycemia and hyperglycemia)

  17. Change in insulin dose

    Time frame: Measured at baseline and month 6

    Measured by recording total insulin dose, basal insulin dose, and bolus insulin dose

Sponsors and collaborators

Lead sponsor

University of Illinois at Chicago

Other

Registry information

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Nov 18, 2023
Registry last updated
Mar 2, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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