Ultra-Processed Foods, Palatability, Appetite, and Gastrointestinal Transit

May 20, 2026 updated by: Richard Mattes, Purdue University

Ultra-Processed Foods - Palatability and Appetite

The goal of this clinical trial is to learn how food processing level affects appetite and gastrointestinal transit time when meal palatability is changed. Participants will complete one screening visit and four test visits. During each test visit, participants will consume one of four meals that differ by food processing level and palatability: high-palatability ultra-processed food, low-palatability ultra-processed food, high-palatability non-ultra-processed food, or low-palatability non-ultra-processed food. The main questions this study aims to answer are whether food processing and palatability affect appetite sensations and gastrointestinal transit time. Participants will rate appetite sensations during each test visit and provide breath samples to measure gastrointestinal transit time.

Study Overview

Status

Status

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

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 randomized crossover trial examining the effects of food processing level and palatability on appetite and gastrointestinal transit time. Participants will complete a screening visit followed by four test visits, with each test visit separated by at least one week. Each participant will consume all four test meals: high-palatability ultra-processed food, low-palatability ultra-processed food, high-palatability non-ultra-processed food, and low-palatability non-ultra-processed food. Palatability will be reduced by adding bitter melon powder to the low-palatability meals. During each test visit, participants will consume the assigned test meal containing lactulose as a marker of gastrointestinal transit time. Breath samples will be collected to assess orocecal transit time using hydrogen analysis. Participants will also rate meal palatability and appetite sensations, including hunger, fullness, desire to eat, amount they could eat, and thirst, using visual analog scales during the test visit.

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 (Actual)

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.
40

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 Locations

  • United States
    • Indiana
      • West Lafayette, Indiana, United States, 47907
        • Purdue 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

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

Yes

Description

Inclusion Criteria:

  • Individuals aged 18 to 60 years.
  • Any sex, gender, or orientation.
  • Self-reported good health.
  • No medication use.
  • No allergies or food sensitivities to any of the foods used in the study.
  • No anticipated change in physical activity during the study period.
  • Willingness to complete all planned study activities, including the screening visit and four test visits.
  • At screening, participants must rate the selected high-palatability foods between 60 and 90 on a 100-unit visual analog scale, where 100 = extremely palatable.
  • At screening, participants must rate the selected low-palatability foods between 10 and 40 on a 100-unit visual analog scale.

Exclusion Criteria:

  • Younger than 18 years or older than 60 years.
  • Current medication use.
  • Allergies or food sensitivities to any study foods.
  • Not meeting the required palatability rating ranges during screening.
  • Anticipated change in physical activity during the study period.
  • Not self-reporting good health.
  • Unwillingness or inability to complete the planned study activities.

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

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: Palatable Ultra-Processed Food
Participants will consume a palatable ultra-processed test meal during one study visit. The meal will be used to assess appetite sensations, palatability ratings, and gastrointestinal transit time.
Other: Palatable Ultra-Processed Food Meal
Participants will consume a palatable ultra-processed test meal during one study visit. The meal will consist of commonly available ultra-processed food items and will be used to assess appetite sensations, meal palatability, and gastrointestinal transit time.
Experimental: Unpalatable Ultra-Processed Food
Participants will consume an unpalatable ultra-processed test meal during one study visit. Palatability will be reduced by adding bitter melon powder. The meal will be used to assess appetite sensations, palatability ratings, and gastrointestinal transit time.
Other: Unpalatable Ultra-Processed Food Meal
Participants will consume an unpalatable ultra-processed test meal during one study visit. Palatability will be reduced by adding organic bitter melon powder to the ultra-processed meal. The meal will be used to assess appetite sensations, meal palatability, and gastrointestinal transit time.
Experimental: Palatable Non-Ultra-Processed Food
Participants will consume a palatable non-ultra-processed test meal during one study visit. The meal will be used to assess appetite sensations, palatability ratings, and gastrointestinal transit time.
Other: Palatable Non-Ultra-Processed Food Meal
Participants will consume a palatable non-ultra-processed test meal during one study visit. The meal will consist of commonly available non-ultra-processed food items and will be used to assess appetite sensations, meal palatability, and gastrointestinal transit time.
Experimental: Unpalatable Non-Ultra-Processed Food
Participants will consume a unpalatable non-ultra-processed test meal during one study visit. Palatability will be reduced by adding bitter melon powder. The meal will be used to assess appetite sensations, palatability ratings, and gastrointestinal transit time.
Other: Unpalatable Non-Ultra-Processed Food Meal
Participants will consume an unpalatable non-ultra-processed test meal during one study visit. Palatability will be reduced by adding organic bitter melon powder to the non-ultra-processed meal. The meal will be used to assess appetite sensations, meal palatability, and gastrointestinal transit time.

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
Orocecal Transit Time
Time Frame: During each test visit, up to 4.5 hours after meal consumption
Orocecal transit time will be assessed using hydrogen analysis of end-alveolar breath samples collected after consumption of each test meal. Each test meal will contain lactulose as a marker of gastrointestinal transit time.
During each test visit, up to 4.5 hours after meal consumption
Appetite Sensations
Time Frame: During each test visit, up to 4.5 hours after meal consumption
Appetite sensations, including hunger, fullness, desire to eat, prospective food consumption, and thirst, will be assessed using 100-mm visual analog scales during each test visit after consumption of the assigned test meal every 30 minutes. Each visual analog scale ranges from 0 to 100 mm, with higher scores indicating a greater intensity of the rated sensation. Higher scores are not inherently better or worse outcomes, but reflect greater hunger, fullness, desire to eat, prospective food consumption, or thirst, depending on the item.
During each test visit, up to 4.5 hours after meal consumption
Meal Palatability Ratings
Time Frame: During each test visit, up to 4.5 hours after meal consumption
Meal palatability will be assessed using a 100-mm general labeled magnitude scale during each study visit. The scale ranges from 0 to 100 mm, with 0 mm anchored by "most disliked sensation imaginable," 50 mm anchored by "neutral," and 100 mm anchored by "most liked sensation imaginable." Higher scores indicate greater liking of the test meal and therefore a more favorable palatability rating.
During each test visit, up to 4.5 hours after meal consumption

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.
Purdue 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)

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.
September 24, 2024

Primary Completion (Actual)

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.
April 30, 2026

Study Completion (Actual)

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.
April 30, 2026

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).
May 14, 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.
May 14, 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.
May 20, 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.
May 22, 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 20, 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.
  • IRB-2024-450

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because the current IRB-approved protocol does not include a formal plan for external individual participant data sharing. Study data will be de-identified for analysis, and identifying information will be stored separately from study data. Code numbers linking participants to their data will be destroyed according to the approved protocol. No information by which participants can be identified will be released or published.

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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