Low-Carb/Time-restricted Feeding Protocol in Insulin-Using Type 2 Diabetics

Feasibility Study of a Low-Carb/Time-restricted Feeding Protocol in Insulin-Using Type 2 Diabetics

The current paradigm of Type 2 Diabetes treatment relies heavily on expensive pharmacotherapy even though lifestyle factors are at the root of the condition. This study is designed to assess the feasibility of a low carbohydrate diet coupled with a time restricted feeding intervention to improve participant sensitivity, reducing their need for insulin. 20 participants will be invited to enroll from the 20 S Park St Clinic in Madison, WI and remain on study for up to 6 months.

Study Overview

• Status: Completed
• Conditions: Type2 Diabetes
• Intervention / Treatment: Other: Low Carbohydrate Diet; Other: Time Restricted Feeding

Detailed Description

The investigators will perform a prospective cohort study of 20 insulin-using Type 2 diabetics who have primary care providers at 20 S Park St Clinic. Participants will be recruited from the Internal Medicine practices at the clinic. The subjects will meet with Dr. Zimmermann (Study Clinician) to review time restricted feeding and low-carbohydrate diets as well as a strategy for decreasing insulin doses. Calls from Dr. Zimmermann's clinic nurse will occur daily until blood glucose levels stabilize to manage insulin decrease.

Participants will complete monthly logs of food intake times and meet with a dietician twice during the 6-month study. Diabetes medication use will be reviewed, and hemoglobin A1c will be measured, at baseline and at 3 and 6 months. The participants' non-diabetic medical care will continue to be managed through their primary care physicians (PCPs).

Specific Aims:

• Demonstrate feasibility of the low carbohydrate/time restricted feeding (LC/TRF) protocol

  • Feasibility will be assessed based on participant compliance with time-restricted feeding and recommended carbohydrate intake, clinician time and clinic resources

• Determine effectiveness of the LC/TRF protocol on diabetes care and quality of life

  • Effectiveness on diabetes care will be evaluated using changes in A1c, insulin use, BMI, patient quality of life, and adverse events including hypoglycemia.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Wisconsin
    • Madison, Wisconsin, United States, 53704
      • UW Health Union Corners Clinic
    • Madison, Wisconsin, United States, 53705
      • University of Wisconsin Hospital and Clinics
    • Madison, Wisconsin, United States, 53717
      • UW Health West Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Patient of a primary care provider at 20 S Park Internal Medicine Clinic
• Insulin using type 2 diabetic
• Using glargine or detemir insulin for basal insulin dosing
• Self-administering insulin
• Hemoglobin A1c 7-10%.
• Stable diabetes regimen for >3 months
• Demonstrated reliability with glucose monitoring, A1c checks
• BMI 25-35

Exclusion Criteria:

• History consistent with type 1 diabetes
• Using concentrated insulin (U200 or U300)
• Living in a skilled nursing facility
• Unwilling or unable to do frequent (3x daily) blood glucose checks
• eGFR (estimated glomerular filtration rate) < 30 mL/min per 1.73 m2
• Currently on steroids or warfarin
• Hospitalized within 3 months
• Symptomatic heart failure
• Weight Loss >10% in last six months
• History of organ transplantation
• Pregnant/trying to become pregnant/breast feeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low Carb / Time Restricted Feeding; Participants will eat a low carbohydrate diet (30-60 grams) in a time restricted feeding window (2 meals within 8 hours) daily for the duration of the study (6 months).	Other: Low Carbohydrate Diet; Dietary choices are counseled to come primarily from lean meats, eggs, nuts, seeds, vegetables and berries.; Other: Time Restricted Feeding; Participants will be asked to have 2 meals within an 8 hour period, preferably before 2pm.; Other Names: Intermittent Fasting

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Effectiveness of Intervention: Changes in Hemoglobin A1c	Changes in A1c will be measured at baseline, 3 and 6 month MD visits. Data will be extracted from HealthLink by chart review. Comparisons will be made between post-intervention A1c scores and baseline scores, at 1 month and at 3 months using paired t-tests to detect whether patients experienced a positive outcome.	baseline, 3 months, 6 months
Effectiveness of Intervention: Changes in Insulin Dosage	Changes in insulin dosage will be measured at baseline, 3 and 6 month MD visits. Data will be extracted from HealthLink by chart review.	baseline, 3 months, 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Participant Satisfaction	Participant satisfaction with the protocol will be assessed at 3 and 6 months. This will include questions about difficulty, barriers to implementation, and impact on family. Quantitative and qualitative analysis will be performed to determine barriers and facilitators to maintaining TRF and low carbohydrate diet. Semi-structured phone interviews will be performed with 10 of the patients (5 who maintained the LC/TRF protocol and 5 who did not) to understand the impact of the TRF and low carbohydrate diet on their daily lives and determine barriers and facilitators. Interviews will be transcribed and thematic analysis will be performed.	3 months, 6 months
Change in Appraisal of Diabetes Scale (ADS) Score	Participant quality of life (QoL) will be assessed at baseline, 3 and 6 months with the Appraisal of Diabetes Scale (ADS). The ADS is a validated tool to measure patients' appraisal of how well they can care for their diabetes and its impact on their life. It is a 7-item survey with each question scored on a likert scale (1-5) for a total range of possible scores 7-35, where lower scores indicate better QoL. Statistical analysis will be performed using paired t-tests or non-parametric methods based on distribution to evaluate ADS changes over time.	baseline, 3 months, 6 months
Clinic-level feasibility: Average Hours of Support Time per Participant	MD and RD clinic time along with RN phone support will be logged with each encounter to provide a quantitative assessment of the resources required to implement this type of intervention on a clinic scale. Descriptive statistics with means and standard deviations per patient will be calculated for each class of health care provider.	up to 6 months
Effectiveness of Intervention: Changes in BMI	Changes in BMI will be measured at baseline, 3 and 6 month MD visits. Data will be extracted from HealthLink by chart review. Weight and height will be combined to report BMI in kg/m^2.	baseline, 3 months, 6 months
Feasibility: Percent of days where food was eaten within the target timeframe	Participant compliance with time-restricted feeding will be evaluated using monthly journals logging first and last food intake each day. The journals will be mailed to Dr. Zimmermann via pre-addressed/stamped security envelopes or brought to appointments. Time-restricted feeding compliance will be calculated using descriptive statistics to determine the % of days where all food was eaten within the target timeframe. Analysis will be done for all data available, data from participants with logs for >50% of days, and participants with logs for >75% of days.	up to 6 months
Feasibility: Average Daily Calories	Participant compliance with recommended carbohydrate intake will be evaluated based on data from the registered dietitian (RD) dietary review. RD will calculate daily grams of carbohydrate and total calories. Compliance will be calculated with descriptive statistics for % of days compliant with <30g, 30-60g, >60g of carbohydrates as well as average daily calories.	up to 6 months
Feasibility: Percent of day compliant with Carbohydrate target	Participant compliance with recommended carbohydrate intake will be evaluated based on data from the registered dietitian (RD) dietary review. RD will calculate daily grams of carbohydrate and total calories. Compliance will be calculated with descriptive statistics for % of days compliant with <30g, 30-60g, >60g of carbohydrates as well as average daily calories.	up to 6 months

Collaborators and Investigators

• Sponsor: University of Wisconsin, Madison
• Investigators: Principal Investigator: David Feldstein, MD, UW School of Medicine and Public Health

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2021
• Primary Completion (Actual): January 24, 2022
• Study Completion (Actual): January 24, 2022

Study Registration Dates

• First Submitted: September 9, 2020
• First Submitted That Met QC Criteria: September 16, 2020
• First Posted (Actual): September 22, 2020

Study Record Updates

• Last Update Posted (Actual): March 14, 2022
• Last Update Submitted That Met QC Criteria: March 11, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Keywords: insulin sensitivity; low carbohydrate diet; time restricted feeding
• Other Study ID Numbers: 2020-0140; A534253 (Other Identifier: UW- Madison); SMPH/MEDICINE/GEN INT MD (Other Identifier: UW Madison); Protocol Version 4/20/2020 (Other Identifier: UW Madison)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No