Snacking Effects on the Brain Response to Foods and Satiety During Dieting

March 19, 2026 updated by: University of Colorado, Denver
This study plans to learn more about how different types of snacks may affect brain processes relating to eating behaviors during a diet intervention.

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.

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.
70

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.

Study Contact Backup

Study Locations

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Recruiting
        • University of Colorado Anschutz Medical Campus
        • Contact:
        • Contact:
        • Principal Investigator:
          • Kristina T Legget, PhD

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

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 25-45 years old
  • BMI at least 27 kg/m2
  • Comfortable completing a weight-loss intervention\
  • Willing to consume a daily snack of either walnuts or pretzels

Exclusion Criteria:

  • Nut or wheat allergy
  • History of bariatric surgery
  • Current eating disorder
  • Current illicit substance use
  • Current pregnancy, lactation (or less than 3 months after stopping lactation), or less than 6 months postpartum
  • Uncontrolled hypertension (>160/100 mmHg)
  • Significant endocrine/metabolic disease kidney disease, liver disease, or blood disease that would be anticipated to affect study results
  • Taking injectable medications, sulfonylureas, or meglitinides for diabetes treatment
  • Taking weight-loss medications, or steroids within ~3 months prior to study participation (e.g., GLP-1 receptor agonists)
  • Significant mental health changes within ~3 months prior to study participation (e.g., medication adjustments, new psychiatric diagnoses, hospitalization relating to mental health concerns)
  • Neurological illnesses or injury that would be anticipated to affect MRI data
  • Weight change greater than 10% within 3 months prior to study participation
  • Currently participating in another weight-loss study
  • Not comfortable eating the study-provided meals (with allowances for dietary preferences) and/or following a highly restrictive diet (e.g., vegan)
  • MRI-specific exclusion criteria (e.g., metal in the body, weight >500 lbs

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: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

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: Snack Type 1: Walnuts
Participants will complete a 12 week diet intervention, during which they will be asked to reduce their daily caloric intake. During the diet intervention, participants in the Snack Type 1 group will be asked to eat a daily snack of walnuts, which will be provided by the study team. Participants will meet with study staff on a weekly basis during the intervention (with some meetings virtual and in-person visits every 2-3 weeks).
Other: Snack Type 1: Walnuts
Participants will complete a 12 week diet intervention, during which they will be asked to reduce their daily caloric intake. During the diet intervention, participants in the Snack Type 1 group will be asked to eat a daily snack of walnuts, which will be provided by the study team.
Active Comparator: Snack Type 2: Pretzels
Participants will complete a 12 week diet intervention, during which they will be asked to reduce their daily caloric intake. During the diet intervention, participants in the Snack Type 2 group will be asked to eat a daily snack of pretzels, which will be provided by the study team. Participants will meet with study staff on a weekly basis during the intervention (with some meetings virtual and in-person visits every 2-3 weeks).
Other: Snack Type 2: Pretzels
Participants will complete a 12 week diet intervention, during which they will be asked to reduce their daily caloric intake. During the diet intervention, participants in the Snack Type 2 group will be asked to eat a daily snack of pretzels, which will be provided by the study team.

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
Percent change in Blood Oxygen Level Dependent (BOLD) response to visual food cues as measured by functional magnetic resonance imaging
Time Frame: Baseline, 12 weeks
Percent change in blood oxygen level dependent (BOLD) response from baseline to after the 12-week intervention while viewing visual food cues will be measured using functional magnetic resonance imaging (fMRI), focusing on insula, striatum, amygdala, and prefrontal cortex.
Baseline, 12 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 percent body fat
Time Frame: Baseline, 12 weeks
Change in percent body fat from baseline to after the 12-week intervention.
Baseline, 12 weeks
Change in appetite response to a meal
Time Frame: Baseline, 12 weeks
Change in appetite response to a meal (area under the curve for visual analog scale [VAS] ratings of hunger and satiety across fasted and fed states) from baseline to after the 12-week intervention.
Baseline, 12 weeks
Change in food cravings
Time Frame: Baseline, 12 weeks
Change in food cravings (using the Food Cravings Questionnaire) from baseline to after the 12-week intervention
Baseline, 12 weeks
Change in dietary restraint
Time Frame: Baseline, 12 weeks
Change in dietary restraint (measured using the dietary restraint subscale of the Three Factor Eating Questionnaire) from baseline to after the 12-week intervention.
Baseline, 12 weeks
Change in reward-based eating drive
Time Frame: Baseline, 12 weeks
Change in reward based eating drive (measured using the Reward-Based Eating Drive-13 questionnaire) from baseline to after the 12-week intervention.
Baseline, 12 weeks
Change in waist circumference
Time Frame: Baseline, 12 weeks
Change in waist circumference (cm) from baseline to after the 12-week intervention
Baseline, 12 weeks
Change in body weight
Time Frame: Baseline, 12 weeks
Change in body weight (kg) from baseline to after the 12-week intervention
Baseline, 12 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.
University of Colorado, Denver

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.
California Walnut Commission

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Kristina T Legget, PhD, University of Colorado, Denver

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.
March 5, 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.
March 31, 2028

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.
March 31, 2028

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).
February 12, 2026

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.
February 19, 2026

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.
February 23, 2026

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.
March 23, 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.
March 19, 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.
March 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.
  • 25-1900

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

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.

Clinical Trials on Overweight/Obesity

Clinical Trials on Snack Type 1: Walnuts

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings