Precision Diets for Diabetes Prevention

April 29, 2026 updated by: Michael Snyder, Stanford University
With this study the investigators want to understand the physiological differences for people developing pre-diabetes and diabetes. The investigators hypothesize that different individuals go through different paths in the development of the disease. By understanding the personal mechanism for developing disease, the investigators will find a personalized approach to prevent that development. The investigators are also hoping to be able to find a biomarker that will pinpoint to the particular defect and thus, diagnose the problem at an earlier stage and have the information to give personalized diet recommendations to prevent the development of diabetes more effectively.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

At present, individuals with prediabetes or diabetes are grouped together as a single entity, but almost certainly they represent a mix of different gene-environment interactions that lead to one of four dominant physiologic mechanisms underlying their dysglycemia. 1- liver insulin resistance, 2- muscle insulin resistance, 3- impaired insulin secretion, 4- impaired incretin hormone secretion. Gaps that we are addressing here are extremely important - first, we will define a composite biomarker to identify different subphenotypes of prediabetes based on the four known physiologic mechanisms that contribute differentially in each individual to glucose elevations, which we hypothesize will also be reflected in their "glucotype". Importantly, because both continuous glucose monitor and administration of standardized meal testing and metabolic tests are not practical in the clinic, the development of a composite biomarker comprised of select multi-omics measures and clinical variables will enable clinicians and possibly patients (without clinician) to easily identify the specific diet that will yield optimal health results.

Study Type

Interventional

Enrollment (Actual)

115

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Stanford, California, United States, 94304
        • Stanford University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Be 18 years of age or older;
  • Not be pregnant, if female;

Exclusion Criteria:

  • Have major organ disease, hypertension defined as >160/100, pregnant/lactating, diabetogenic medications, malabsorptive disorders like celiac sprue, others, heavy alcohol use, use of weight loss medications or specific diets, weight change > 2 kg in the last three weeks, history of bariatric surgery.
  • Any medical condition that physicians believe would interfere with study participation or evaluation of results.
  • Mental incapacity a nd/or cognitive impairment on the part of the patient that would preclude adequate understanding of, or cooperation with, the study protocol.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Optimizing Diet for Glycemic Control

Phase 1: Metabolic testing will include 3 metabolic tests:

  1. The Oral Glucose Tolerance Test. The participant will wear the CGM while undergoing the OGTT + will be asked to repeat the test at home twice.
  2. The Insulin Sensitivity Test (Steady State Plasma Glucose). This test is designed to measure how well cells remove glucose from the blood in response to insulin.
  3. The Isoglycemic Intravenous Glucose Infusion (IIGI). This test is designed to measure the incretin hormone effect.

Phase 2: Participants follow their own diet while using the CGM. Participants are provided with 5-10 standardized foods to test during this phase.

Phase 3: Participants are provided with additional standardized foods and counseled to continue their own diet during this phase.

Phase 4: Participants are counseled on reducing or limiting the foods that caused glucose spikes and they are also counseled on macronutrient composition of their diet based on lipid profile.
Other: Dietary
Dietary counseling based on results of CGM analyses.
Other: Oral Food Challege
Participants ate a variety of foods, to assess their impact on blood sugars.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Glycemic Control as Measured by Change Blood Sugar Values
Time Frame: Assessed at a meal (2 to 6 weeks after baseline), starting just prior eating, for a period of 3 hours
Change in glycemic control measured from baseline through all phases of study, stratified according food type and metabolic sub-type. Glycemic control is derived from continuous glucose monitor (CGM) data and expressed in milligrams/deciliter.
Assessed at a meal (2 to 6 weeks after baseline), starting just prior eating, for a period of 3 hours
Area Under the Receiver Operating Characteristic (ROC) Curve - Classification of Metabolic Subphenotype
Time Frame: Baseline (Day 1)
Classify metabolic subphenotype in individuals without diabetes using a machine learning algorithm applied to the glucose time-series response generated by a 16-point (blood draws) oral glucose tolerance testing (OGTT) done in the clinical research center and at home (using CGM). Participants were categorized as insulin sensitive (IS) if teady state plasma glucose (SSPG) was <120 mg dl-1 and insulin resistant (IR) if their SSPG was ≥120 mg dl-1. For this analysis, disposition index (DI) < 1.58 indicates dysfunctional β-cell function, whereas DI ≥ 1.58 indicates normal β-cell function.
Baseline (Day 1)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Area Under the Curve (AUC) of Blood Glucose Level
Time Frame: Assessed at a meal (2 to 6 weeks after baseline), starting just prior eating, for a period of 3 hours
Measured from baseline through all phases of study, from continuous glucose monitor (CGM) data, and stratified according food type and metabolic sub-type.
Assessed at a meal (2 to 6 weeks after baseline), starting just prior eating, for a period of 3 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Stanford University

Collaborators

National Human Genome Research Institute (NHGRI)

Investigators

  • Principal Investigator: Michael P Snyder, PhD, Stanford University
  • Principal Investigator: Tracey McLaughlin, MD, Stanford University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 24, 2018

Primary Completion (Actual)

October 18, 2023

Study Completion (Actual)

October 18, 2023

Study Registration Dates

First Submitted

December 20, 2018

First Submitted That Met QC Criteria

April 17, 2019

First Posted (Actual)

April 18, 2019

Study Record Updates

Last Update Posted (Actual)

May 22, 2026

Last Update Submitted That Met QC Criteria

April 29, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 43883
  • 5RM1HG007735-09 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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