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Completed

NCT Number: NCT07600281

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

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.

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Key information

Conditions

Appetite Behavior Behavior, Animal Eating Behavior Feeding Behavior Food Palatability Food Processing Gastrointestinal Transit

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Purdue University

West Lafayette, Indiana, 47907, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

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

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.

Treatment and study plan

Palatable Ultra-Processed Food Meal

Other

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.

Unpalatable Ultra-Processed Food Meal

Other

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.

Palatable Non-Ultra-Processed Food Meal

Other

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.

Unpalatable Non-Ultra-Processed Food Meal

Other

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.

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

Sponsors and collaborators

Lead sponsor

Purdue University

Other

Registry information

Official study title

Ultra-Processed Foods - Palatability and Appetite

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
May 20, 2026
Registry last updated
May 22, 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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