Cardiometabolic Effects of Pecan Snacking in Prediabetes

May 22, 2026 updated by: Kristina Petersen PhD, APD, FAHA, Penn State University

Glycemic Effects of Substituting Pecans for Snacks Higher in Saturated Fat and Added Sugars in Individuals With Prediabetes

The purpose of this study is to investigate the effects of replacing snacks higher in saturated fats and added sugars with pecans on blood sugar control, heart health and diet quality in individuals with prediabetes. Participants will be randomized into one of two groups. Group 1 will consume 1.5 oz of pecans per day in place of normally consumed snacks higher in saturated fat and added sugars for 16 weeks. Group 2 will be asked to continue consuming their current diet for 16 weeks. Measures will be taken to evaluate blood sugar, heart health and dietary intake at the beginning and 16 weeks later.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a 16-week randomized controlled trial. Participants will be randomized to either: 1) replace current snacks higher in saturated fat and added sugars with 1.5 oz/day of pecans; 2) continue their habitual diet. At the beginning and the end of the 16-week study period, testing will be conducted.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
147

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Kristina Petersen, PhD
  • Phone Number: 814-865-7206
  • Email: kup63@psu.edu

Study Contact Backup

Study Locations

  • United States
    • Pennsylvania
      • University Park, Pennsylvania, United States, 16802
        • Recruiting
        • The Pennsylvania State University
        • Contact:
          • Kristina Petersen, PhD
          • Phone Number: 814-865-7206
          • Email: kup63@psu.edu

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 25-65 years
  • Prediabetes assessed by an HbA1c of 5.7-6.4% at screening
  • BMI 25-40 kg/m2 at screening
  • Low habitual nut consumption (<3.5 oz-eq/week) assessed at the telephone screening
  • Regularly eats snacks higher in saturated fat and/or added sugars assessed at the telephone screening

Exclusion Criteria:

  • LDL-C ≥190 mg/dL at screening
  • Hemoglobin <13.2 g/dL at screening
  • Fasting triglycerides >350 mg/dL at screening
  • ≥10% change in body weight within the 6 months prior to enrollment
  • Blood pressure >140/90 mmHg at screening
  • Type 1 or type 2 diabetes
  • Prescription of anti-hypertensive, lipid-lowering, or glucose-lowering drugs
  • Intake of supplements or over-the-counter medications that affect the outcomes of interest (i.e., lipid, blood pressure, or glucose lowering; vitamin C or multi-vitamins containing vitamin C) and are unwilling to cease during the study period.
  • History of liver, kidney, or autoimmune disease
  • Prior cardiovascular event (e.g., stroke, heart attack)
  • Current pregnancy or intention of pregnancy within the next 12 months
  • Lactation within the prior 6 months
  • Pecan allergy/intolerance/sensitivity/dislike
  • Unwilling/unable to eat 1.5 oz of pecans every day as a snack during the duration of the study
  • Antibiotic use within the prior 4 weeks
  • Oral steroid use within the prior 4 weeks
  • Use of tobacco or nicotine-containing products within the past 6 months
  • History of cancer at any site within the past 10 years (eligible if ≥10 years without recurrence) or non-melanoma skin cancer within the past 5 years (eligible if ≥5 years without recurrence)
  • Participation in another clinical trial within 60 days of baseline
  • Unwilling to contact study staff before enrolling in other health-related research and avoid participating in any research that may interfere with this study.
  • Currently following a restricted or weight-loss diet
  • Prior bariatric surgery
  • Intake of >14 alcoholic drinks/week and/or not willing to avoid alcohol consumption for 48 hours prior to test visits
  • Principal Investigator discretion related to the potential participant's ability to adhere to the study requirements, including being able to come to attend visits
  • Does not speak and/or understand English
  • Unwilling to refrain from donating blood or plasma during the study
  • Weight <110 lb
  • If a potential participant takes thyroid medicine, abnormal thyroid stimulated hormone (TSH) concentration (TSH outside of normal range), or change in dose of thyroid medication within the last 6 months

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Pecan snacking group
Participants will be provided with 1.5 oz/day of pecans and asked to eat these instead of typically consumed snacks higher in saturated fat and added sugars.
Behavioral: Pecan snacking
Replacement of typically consumed snacks with 1.5 oz/day of pecans
Active Comparator: Usual diet
Participants will be asked to continue consuming their usual diet. To match attention and resources, participants will be provided with a grocery voucher in approximately equivalent value to the pecans.
Other: Usual diet
Continue with usual diet

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in HbA1c
Time Frame: 16 weeks
HbA1c will be assessed at baseline and 16-weeks and expressed as percentage . The change in HbA1c will be calculated by subtracting the baseline value from the 16 week value and expressed as percentage point change.
16 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in fasting glucose
Time Frame: 16 weeks
Change in fasting plasma glucose expressed as mg/dL. Change in glucose will be calculated as the mean of the 16 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in mean glucose
Time Frame: 16 weeks
Change in mean glucose assessed by a continuous glucose monitor (CGM) expressed as mg/dL. Change in mean glucose will be calculated as mean glucose assessed from 7 days of CGM wear at 16 weeks minus mean glucose assessed from 7 days of CGM wear at baseline.
16 weeks
Change in mean time in range
Time Frame: 16 weeks
Change in mean time in range (glucose 70-140 mg/dL) assessed by a continuous glucose monitor (CGM) expressed as minutes per day. Change in mean time in range will be calculated as mean time in range assessed from 7 days of CGM wear at 16 weeks minus mean time in range assessed from 7 days of CGM wear at baseline.
16 weeks
Change in glycemic variability
Time Frame: 16 weeks
Change in mean glycemic variability assessed by a continuous glucose monitor (CGM) expressed as the coefficient of variability. Change in mean glycemic variability will be calculated as mean glycemic variability assessed from 7 days of CGM wear at 16 weeks minus mean glycemic variability assessed from 7 days of CGM wear at baseline.
16 weeks
Change in fasting insulin
Time Frame: 16 weeks
Change in fasting serum insulin expressed as micro IU/mL. Change in insulin will be calculated as the mean of the 16 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in homeostatic model of insulin resistance (HOMA-IR)
Time Frame: 16 weeks
Homeostatic model of insulin resistance (HOMA-IR) will be calculated from insulin and glucose measured from a fasting blood sample. Calculated as (insulin × glucose) / 22.5. Change in HOMA-IR will be calculated as the mean of the 16 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in the lipoprotein insulin resistance index
Time Frame: 16 weeks
The lipoprotein insulin resistance index will be calculated from Nuclear Magnetic Resonance assessed lipoprotein concentrations according to a previously described method: Metab, Syndr. Relat. Disord. 12 (8) (2014) 422-429. Change will be calculated by subtracting the baseline value from the 16 week value.
16 weeks
Change in LDL-Cholesterol
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/dL. Change in LDL-cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in apolipoprotein B
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/dL. Change in apolipoprotein B will be calculated by subtracting the baseline value from the 16 week value.
16 weeks
Change in non-HDL cholesterol
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/dL. Change in non-HDL cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in Total Cholesterol
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/dL. Change in total cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in HDL-Cholesterol
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/dL. Change in HDL-cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in Triglycerides
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/dL. Change in triglycerides will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in C-reactive protein
Time Frame: 16 weeks
Assessed from fasting blood draw expressed in mg/L. Change in C-reactive protein will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).
16 weeks
Change in Central Systolic and Diastolic Blood Pressure
Time Frame: 16 weeks
Central blood pressure measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline & 16 weeks. Change will be calculated by subtracting the baseline value from the end point value.
16 weeks
Change in Peripheral Systolic and Diastolic Blood Pressure
Time Frame: 16 weeks
Peripheral blood pressure measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline & 16 weeks. Change will be calculated by subtracting the baseline value from the end point value.
16 weeks
Change in Carotid-Femoral Pulse Wave Velocity
Time Frame: 16 weeks
Measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline & 16 weeks. Change will be calculated by subtracting the baseline value from the end point value.
16 weeks
Change in particle size and number of LDL, HDL, triglyceride rich lipoproteins
Time Frame: 16 weeks
Measured via Nuclear Magnetic Resonance at baseline and 16 weeks. The change will be calculated by subtracting the baseline value from the 16 week value.
16 weeks
Change in Saturated fat intake
Time Frame: 16 weeks
Assessed from 24-hour recalls completed prior to baseline and at 16 weeks. Change in saturated fat will be calculated as saturated fat intake at 16 weeks minus baseline saturated fat intake.
16 weeks
Change in added sugar intake
Time Frame: 16 weeks
Assessed from 24-hour recalls completed prior to baseline and at 16 weeks. Change in added sugar intake will be calculated as added sugar intake at 16 weeks minus baseline added sugar intake.
16 weeks
Change in diet quality
Time Frame: 16 weeks
Assessed from 24-hour recalls completed prior to baseline and at 16 weeks. Diet quality will be calculated according to the Healthy Eating Index-2020 (HEI). Change in HEI will be calculated as HEI at 16 weeks minus baseline HEI.
16 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Penn State University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
American Pecan Promotion Board

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 22, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 30, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 14, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 14, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 19, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PEC

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data will be deposited into an open access repository once results from all pre-specified primary and secondary outcomes are published.

IPD Sharing Time Frame

The SAP and protocol will be posted on clinicaltrials.gov prior to enrollment commencing.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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