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NCT Number: NCT07428187

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

This study plans to learn more about how different types of snacks may affect brain processes relating to eating behaviors during a diet intervention.

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Key information

Conditions

Overweight/Obesity Body Weight Body Weight Changes Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms Weight Loss

Age range

25 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Snack Type 1: Walnuts

Other

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: Pretzels

Other

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.

Primary outcomes

  1. 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.

Secondary outcomes

  1. Change in percent body fat

    Time frame: Baseline, 12 weeks

    Change in percent body fat from baseline to after the 12-week intervention.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Change in waist circumference

    Time frame: Baseline, 12 weeks

    Change in waist circumference (cm) from baseline to after the 12-week intervention

  7. Change in body weight

    Time frame: Baseline, 12 weeks

    Change in body weight (kg) from baseline to after the 12-week intervention

Study contacts

Contact information is provided by the study sponsor or research team.

Allison Hild, BS

CONTACT

[email protected]

3037249024

Kristina T Legget, PhD

CONTACT

[email protected]

303-724-5809

Sponsors and collaborators

Lead sponsor

University of Colorado, Denver

Other

Collaborators

  • California Walnut Commission

Registry information

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
Feb 23, 2026
Registry last updated
Mar 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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