The Lifestyle Education About Prediabetes (Leap) Study (LEAP)

Testing a Very Low-carbohydrate Diet Version of the Diabetes Prevention Program to Reduce Risk Factors for Type 2 Diabetes: The LEAP (Lifestyle Education About Prediabetes) Study

This research will test whether a standard version or very low-carbohydrate version of the Diabetes Prevention Program better improves outcomes like blood glucose control and body weight for patients with prediabetes.

Participants will have screening (includes blood draw) and baseline testing with a continuous glucose monitor. Once these enrollment steps are completed and the participants will be randomized to one of two groups: standard National Diabetes Prevention Program (NDPP) or a very low-carbohydrate version.

In addition to the diet (12 months) participants will be asked to participate in hour-long weekly group classes over zoom. After four months in the program, classes will occur about every month to help participants maintain the new diet. There will also be check-ins and follow-up visits through out the study.

Study Overview

• Status: Completed
• Conditions: PreDiabetes
• Intervention / Treatment: Behavioral: Standard NDPP; Behavioral: Very low-carbohydrate diet

• Study Type: Interventional
• Enrollment (Actual): 304
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• overweight, defined as BMI >= 25 kg/m2 >= 23 kg/m2 if of Asian descent
• HbA1c between 5.7% - 6.4% verified at baseline
• willingness to participate in group-based sessions
• able to engage in at least light physical activities such as walking
• willingness to follow a prescribed diet, be randomized, self-weight, track diet, and report physical activity minutes
• physician approval to participate

Exclusion Criteria:

• history of type 1 diabetes or type 2 diabetes
• use of anti-obesity medications or participation in another weight loss program or intervention
• use of glucose lowering medications other than metformin
• pregnant or planning to become pregnant during the intervention period
• breastfeeding
• use of oral corticosteroids
• previous bariatric surgery or planning to have bariatric surgery during the study period
• blood disorders that influence HbA1c, including frequent blood transfusions, phlebotomy, anemia, hemoglobinopathy, polycythemia
• any condition for which the study team deems participation to be unsafe or inappropriate
• inability to read, write, or speak English
• inability to provide informed consent
• adherence to a vegan or vegetarian diet
• adherence to a very low-carbohydrate (keto) diet
• difficulty chewing or swallowing
• no influence over what foods are purchased, prepared, and/or served
• above weight limit for DEXA (500 pounds)
• untreated eating disorder or mental health conditions, such as depression with suicidal ideation, bipolar or schizophrenia with psychosis
• use of warfarin
• chronic kidney disease, stage 4 or higher
• use of loop diuretics: 20mg or higher of furosemide or equivalent (Lasix (furosemide), Bumex (bumetanide), Ederin or Sodium Edecrin (ethacrynic acid), Demadex or Soaanz (torsemide))

• any concerning values in baseline labs (participants will be referred to Primary Care Physician and will be allowed to return for later enrollment if labs are no longer concerning)

  • Triglycerides 600 Milligrams per deciliter (mg/dL) or higher
  • Thyroid stimulating hormone of any abnormal value
  • Potassium of any abnormal value

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Standard NDPP; 12-month long, calorie-restricted NDPP	Behavioral: Standard NDPP; Participants in this arm will be taught to manage their prediabetes with the Centers for Disease Control's standard National Diabetes Prevention Program. It teaches a lower calorie, lower fat diet. There will be a core phase and a maintenance phase of this study; the core phase will last for about 4 months and will involve weekly or every other week classes, home assignments, and brief check-in surveys. The maintenance phase will last for the remaining time, with classes and check-in surveys approximately once a month.
Experimental: Very low-carbohydrate diet (VLCD); VLCD is an adaptation of the standard NDPP curriculum, which preserves all features with the exception of altered dietary advice.	Behavioral: Very low-carbohydrate diet; Participants in this arm will be taught to manage their prediabetes with the Centers for Disease Control's National Diabetes Prevention Program, adapted to teach a very low-carbohydrate diet, also called a ketogenic or "keto" diet. This diet involves eating non-starchy vegetables, leafy greens, cheese, meats, berries, nuts, and seeds and avoiding starchy foods like pasta, bread, rice, beans, many fruits, etc. There will be a core phase and a maintenance phase of this study; the core phase will last for about 4 months and will involve weekly or every other week classes, home assignments, and brief check-in surveys. The maintenance phase will last for the remaining time, with classes and check-in surveys approximately once a month.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in HbA1c	HbA1c levels will be measured by standard immunoturbidimetric assay methods and quality control measures at a Clinical Laboratory Improvement Amendments (CLIA) certified lab.	0 to 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Inflammation based on C-reactive protein (CRP)	High-sensitivity C-reactive protein will be measured with nephelometric methods utilizing latex particles coated with CRP monoclonal antibodies and standardized against a CRP reference preparation.	0 to 12 months
Change in percent body weight loss		0-12 months
Change in glycemic variability	This will be measured with an Abbott Libre Pro continuous glucose monitoring device on participants upper arm and the information on the sensor is blinded to participants. The monitoring device will record participants' glucose levels in the interstitial fluid by a glucose oxidase method every 15 minutes, continuously for 14 days at each time point. T The glucose variability and the proportion of time spent in the euglycemic (3-7.8 millimoles per litre (mmol/l)) and hyperglycemic (≥ 11.1 mmol/l for at least 15 minutes) states, following previous standards for interstitial glucose concentrations.	0 to 12 months
Change in small particle low-density lipoproteins (LDL)		0 to 12 months
Change in high-density lipoproteins (HDL)		0 to 12 months
Change in triglycerides		0 to 12 months
Change in HbA1c	HbA1c levels will be measured by standard immunoturbidimetric assay methods and quality control measures at a Clinical Laboratory Improvement Amendments (CLIA) certified lab.	0 to 4 months

Collaborators and Investigators

• Sponsor: University of Michigan
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Principal Investigator: Laura Saslow, PhD, University of Michigan

Publications and helpful links

General Publications

• Griauzde DH, O'Brien A, Yancy WS Jr, Richardson CR, Krinock J, DeJonckheere M, Isaman DJM, Vanias K, Shopinski S, Saslow LR. Testing a very low-carbohydrate adaption of the Diabetes Prevention Program among adults with prediabetes: study protocol for the Lifestyle Education about prediabetes (LEAP) trial. Trials. 2022 Sep 30;23(1):827. doi: 10.1186/s13063-022-06770-3.

Study record dates

Study Major Dates

• Study Start (Actual): March 20, 2022
• Primary Completion (Actual): November 14, 2025
• Study Completion (Actual): November 14, 2025

Study Registration Dates

• First Submitted: February 2, 2022
• First Submitted That Met QC Criteria: February 2, 2022
• First Posted (Actual): February 11, 2022

Study Record Updates

• Last Update Posted (Estimated): December 19, 2025
• Last Update Submitted That Met QC Criteria: December 17, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Nutrition therapy; Diabetes Prevention Program; Very low carbohydrate diet
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Prediabetic State
• Other Study ID Numbers: HUM00196546; R01DK125792-01A1 (U.S. NIH Grant/Contract)

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