Overweight/ObesityNCT07428187
Snacking Effects on the Brain Response to Foods and Satiety During Dieting
A study testing Snack Type 1: Walnuts and Snack Type 2: Pretzels in people with Overweight/Obesity, run by University of Colorado, Denver at 1 site in United States.
Trial summary
This study plans to learn more about how different types of snacks may affect brain processes relating to eating behaviors during a diet intervention. Read more about this study
- Who is it for?
- Ages 25 to 45 years
- Conditions the study is for
- Overweight/Obesity
- What is being tested?
- Snack Type 1: Walnuts and Snack Type 2: Pretzels
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 70 participants
- Where
- 1 siteUnited States
- Study dates
- 5 Mar 2026to 31 Mar 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 45 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- 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
Who cannot join
- 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)
Show all 15Show fewer
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Colorado Anschutz Medical Campus
Aurora, Colorado, 80045
Kristina Legget, PhD, 303-724-5809, kristina.legget@cuanschutz.edu
Allison Hild, BS, 303-724-9024, allison.hild@cuanschutz.edu
About this study
This study plans to learn more about how different types of snacks may affect brain processes relating to eating behaviors during a diet intervention.
- Conditions
- Overweight/Obesity
- Being tested
- Snack Type 1: Walnuts, Snack Type 2: Pretzels
- Keywords
- Dieting, Weight loss, Overweight, Obesity, Food, Neuroimaging, Body weight, Eating, Brain, Magnetic resonance imaging
- Medical subject headings
- Overweight, Obesity, Weight Loss, Body Weight
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Snack Type 1: WalnutsOther
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.
Snack Type 2: PretzelsOther
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.
| Study group | Role | What they receive |
|---|---|---|
| Snack Type 1: Walnuts | Experimental | 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). Receives: Other: Snack Type 1: Walnuts |
| Snack Type 2: Pretzels | Active comparator | 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). Receives: Other: Snack Type 2: Pretzels |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percent change in Blood Oxygen Level Dependent (BOLD) response to visual food cues as measured by functional magnetic resonance imaging
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.
Measured: Baseline, 12 weeks
Secondary outcomes (7)
Change in percent body fat
Change in percent body fat from baseline to after the 12-week intervention.
Measured: Baseline, 12 weeks
Change in appetite response to a meal
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.
Measured: Baseline, 12 weeks
Change in food cravings
Change in food cravings (using the Food Cravings Questionnaire) from baseline to after the 12-week intervention
Measured: Baseline, 12 weeks
Change in dietary restraint
Change in dietary restraint (measured using the dietary restraint subscale of the Three Factor Eating Questionnaire) from baseline to after the 12-week intervention.
Measured: Baseline, 12 weeks
Change in reward-based eating drive
Change in reward based eating drive (measured using the Reward-Based Eating Drive-13 questionnaire) from baseline to after the 12-week intervention.
Measured: Baseline, 12 weeks
Change in waist circumference
Change in waist circumference (cm) from baseline to after the 12-week intervention
Measured: Baseline, 12 weeks
Change in body weight
Change in body weight (kg) from baseline to after the 12-week intervention
Measured: Baseline, 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Feb 2026
- Study start5 Mar 2026
- Primary completion31 Mar 2028 (estimated)
- Study completion31 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Overweight/ObesityStudies of the same condition, open and under way.
- More trials run by University of Colorado, DenverThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 70 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Denver
- Sponsor type
- University, hospital or other
- Collaborators
- California Walnut Commission
- Responsible party
- Sponsor
- Investigators
- Kristina T Legget, PhD, Principal investigator, University of Colorado, Denver
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07428187
- Sponsor's protocol ID
- 25-1900
- Status last verified
- Mar 2026
- First submitted
- 12 Feb 2026
- Last updated
- 23 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Snacking Effects on the Brain Response to Foods and Satiety During Dieting
- ClinicalTrials.gov ID
- NCT07428187
- Acronym / sponsor ID
- 25-1900
- Conditions
- Overweight/Obesity
- Keywords
- Dieting, Weight loss, Overweight, Obesity, Food, Neuroimaging, Body weight, Eating
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 70 participants (estimated)
- Lead sponsor
- University of Colorado, DenverUniversity, hospital or other
- Collaborators
- California Walnut Commission
- Study start
- 5 Mar 2026 (actual)
- Primary completion
- 31 Mar 2028 (estimated)
- Study completion
- 31 Mar 2028 (estimated)
- First posted
- 23 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Snack Type 1: Walnuts | Experimental | Other: Snack Type 1: WalnutsParticipants 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). |
| Snack Type 2: Pretzels | Active comparator | Other: Snack Type 2: PretzelsParticipants 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). |
Who may qualify
- Ages
- 25 to 45 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- 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
Key exclusion criteria (15 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Snack Type 1: WalnutsParticipants 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. | Other | Snack Type 1: Walnuts |
| Snack Type 2: PretzelsParticipants 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. | Other | Snack Type 2: Pretzels |
Primary outcome
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.
7 secondary outcomes
Change in percent body fat
Time frame: Baseline, 12 weeks
Change in appetite response to a meal
Time frame: Baseline, 12 weeks
Change in food cravings
Time frame: Baseline, 12 weeks
Change in dietary restraint
Time frame: Baseline, 12 weeks
Change in reward-based eating drive
Time frame: Baseline, 12 weeks
Change in waist circumference
Time frame: Baseline, 12 weeks
Change in body weight
Time frame: Baseline, 12 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Mar 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Kristina T Legget, PhD principal investigator
University of Colorado, Denver
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Snack Type 1: Walnuts and Snack Type 2: Pretzels in people with Overweight/Obesity, run by University of Colorado, Denver at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Allison Hild, BS (3037249024, allison.hild@cuanschutz.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Mar 2026.