The Effects of GLP-1 Receptor Agonists on Chemosensory Function and Ingestive Behavior

The Effects of GLP-1 Receptor Agonists on Sensory Systems and Ingestive Behavior

The goal of this study is to explore whether of GLP-1 receptor agonist use is associated with differences in taste, smell, food preferences, appetite, food cravings, and responses to food cues in adults. The study includes adults who are not currently taking a GLP-1 receptor agonist but may be eligible to use one, and adults who are already taking a GLP-1 receptor agonist as part of their regular medical care for approximately 1 month or approximately 6 months.

The main questions it aims to answer are:

Are taste and smell function different among adults who are not taking a GLP-1 receptor agonist and adults who have been taking one for different lengths of time? Are food preferences, appetite, food cravings, food reward, attention to food cues, and salivary responses to food cues different among these groups? Researchers will compare adults not currently taking a GLP-1 receptor agonist with adults taking a GLP-1 receptor agonist for approximately 1 month or approximately 6 months. The research team will not prescribe, assign, or provide GLP-1 receptor agonist medications.

People in the study will attend two in-person study visits, complete taste and smell tests, complete food preference and computer-based tasks, and provide saliva samples during a food cue task. Questionnaires about appetite, cravings, food cues, and eating behavior will be completed at home over approximately 2 weeks.

Study Overview

• Status: Completed
• Conditions: Obesity; Overweight; Eating Behavior; Appetite; Taste Perception; Olfaction

Detailed Description

This cross-sectional study examines associations between GLP-1 receptor agonist use, chemosensory function, and ingestive behavior in adults. People enrolled in the study are classified into groups based on GLP-1 receptor agonist use status and duration of use: adults who are not currently taking a GLP-1 receptor agonist but may be eligible to use one, adults taking a GLP-1 receptor agonist for approximately 1 month, and adults taking a GLP-1 receptor agonist for approximately 6 months.

GLP-1 receptor agonist use is not assigned by the research team. People who are taking these medications are using them as part of their regular medical care. The study team does not prescribe, administer, or change GLP-1 receptor agonist treatment.

Study procedures include assessments of taste and smell function, food preferences, food reward, appetite, food cravings, food cue responsivity, attentional responses to food cues, and salivary responses to a food cue. Outcomes will be compared across groups to explore whether GLP-1 receptor agonist use and duration of use are associated with differences in chemosensory function and ingestive behavior.

• Study Type: Observational
• Enrollment (Actual): 90

Contacts and Locations

Study Locations

• United States
  • Indiana
    • West Lafayette, Indiana, United States, 47906
      • Purdue University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18 to 65 years with a Body Mass Index (BMI) greater than 30 kg/m² will be recruited. The study population includes individuals who are eligible to take GLP-1 receptor agonists but have not yet started treatment, and individuals who have been taking GLP-1 receptor agonists for weight management for approximately 1 month or approximately 6 months as part of their regular medical care. Participants will be recruited from the general population and through healthcare providers at IU Health.

Description

Inclusion Criteria:

• Ages 18 to 65 years.
• Any sex or gender.
• Body Mass Index (BMI) >30 kg/m².
• Stable medication use, excluding weight management medications other than GLP-1 receptor agonist use as part of regular medical care.
• Eligible to take GLP-1 receptor agonists but not yet started treatment, or currently taking GLP-1 receptor agonists for weight management for approximately 1 month (±0.5 months) or approximately 6 months (±0.5 months).
• No known sensitivity or allergy to study solutions or foods, including sweet solutions, salty solutions, sour solutions, bitter solutions, fatty stimuli, common food flavors used in testing, milk, and fruit-flavored beverages.

Exclusion Criteria:

• Younger than 18 years or older than 65 years.
• Previous bariatric surgery or planned bariatric surgery within the next year.
• Sensitivity or allergy to study foods, taste solutions, odor stimuli, or food-related test materials.

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Pre-use / Not Currently Taking GLP-1RA; Adults who are not currently taking a GLP-1 receptor agonist but may be eligible to use one based on body weight criteria (BMI > 30). Participants in this group are not assigned to GLP-1 receptor agonist treatment by the study team.
Approximately 1 Month GLP-1RA Use; Adults who have been taking a GLP-1 receptor agonist as part of their regular medical care for approximately 1 month. GLP-1 receptor agonist use is not assigned, prescribed, or modified by the study team.
Approximately 6 Months GLP-1RA Use; Adults who have been taking a GLP-1 receptor agonist as part of their regular medical care for approximately 6 months. GLP-1 receptor agonist use is not assigned, prescribed, or modified by the study team.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Taste Detection Thresholds	Taste detection thresholds will be assessed for sweet, salty, sour, and bitter stimuli (sucrose, sodium chloride, citric acid, and urea, respectively) using a two-alternative forced-choice staircase procedure, in which participants identify which of two samples contains the taste stimulus. Separate outcomes will be reported for each taste quality: sweet, salty, sour, and bitter. For each taste quality, the threshold will be calculated as the geometric mean concentration at which the stimulus is reliably detected and will be reported in mmol/L. Lower threshold values indicate greater taste sensitivity.	During study participation, up to 2 weeks
Suprathreshold Taste Intensity	Suprathreshold taste intensity will be assessed for sweet, salty, sour, and bitter stimuli (sucrose, sodium chloride, citric acid, and urea, respectively) using the general Labeled Magnitude Scale. Separate outcomes will be reported for each taste quality and stimulus concentration. For each taste quality, participants will rate the perceived intensity of suprathreshold stimulus concentrations. The scale ranges from 0 to 100, with 0 anchored by "no sensation" and 100 anchored by "strongest imaginable sensation of any kind." Higher scores indicate greater perceived taste intensity.	During study participation, up to 2 weeks
Taste Hedonics	Taste hedonics will be assessed using a food modification task in which participants create preferred concentrations for sweet, salty, sour, bitter, and fatty stimuli. Separate outcomes will be reported for each stimulus type: sweet, salty, sour, bitter, and fatty. For each stimulus type, the outcome will be the preferred concentration selected by the participant. Higher values indicate preference for a higher concentration of that stimulus and do not necessarily indicate a better or worse outcome.	During study participation, up to 2 weeks
Fat Taste Intensity Rating	Fat taste perception will be assessed using edible strips containing different concentrations of linoleic acid. Participants will rate the perceived intensity of each strip using the general Labeled Magnitude Scale. Separate outcomes will be reported for each linoleic acid concentration. The scale ranges from 0 to 100, with 0 anchored by "no sensation" and 100 anchored by "strongest imaginable sensation of any kind." Higher scores indicate greater perceived fat taste intensity.	During study participation, up to 2 weeks
ArOMa-T Olfactory Test Performance	Olfactory function will be assessed using the ArOMa-T test. Participants will smell odor stimuli and provide computer-based responses to questions assessing olfactory performance. The outcome will be the ArOMa-T test score, with higher scores indicating better olfactory performance.	During study participation, up to 2 weeks
SCENTinel Olfactory Test Performance	Olfactory function will be assessed using the SCENTinel test. Participants will smell odor stimuli and provide computer-based responses to questions assessing odor detection, odor identification, odor intensity, and odor pleasantness. Separate outcomes will be reported for each SCENTinel component. Higher scores indicate better odor detection or identification performance, greater perceived odor intensity, or greater perceived odor pleasantness, depending on the component assessed.	During study participation, up to 2 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Food Preferences	Food preferences will be assessed using the Leeds Food Preference Questionnaire. Participants will view food images and rate how much they like and want to eat each food item. Ratings will be used to assess explicit liking and wanting for foods.	During study participation, up to 2 weeks
Attentional Bias to Food Cues	Attentional bias to food cues will be assessed using a Food Stroop Task. Participants will view food-related and non-food words and respond to the color of each word while ignoring the meaning of the word. Response patterns will be used to assess attentional bias toward food-related cues.	During study participation, up to 2 weeks
Questionnaire-Based Measures of Food Cravings, Food Cue Responsivity, Food Noise, and Eating Behavior	Questionnaire-based measures will be used to assess food cravings, food cue responsivity, food-related intrusive thoughts, perceived food reward, and eating behavior. Participants will complete the Food Cue Responsivity Scale, the Modified Trait and State Food Cravings Questionnaires, the Power of Food Scale, the Food Noise Questionnaire, and the Reasons Individuals Stop Eating Questionnaire. These questionnaires will assess sensitivity to food-related cues, typical and momentary food cravings, food-related intrusive thoughts, perceived responsiveness to the food environment, and reasons for stopping eating, including motivations and physical cues related to meal termination and satisfaction.	During study participation, up to 2 weeks
Dietary Intake	Dietary intake will be assessed using ASA24, the Automated Self-Administered 24-Hour Dietary Assessment Tool. Participants will complete three 24-hour dietary recalls on different days, including two weekdays and one weekend day, to report foods and beverages consumed over the previous 24 hours.	During study participation, up to 2 weeks
Cephalic-Phase Salivary Response	Cephalic-phase salivary response will be assessed by measuring saliva production at baseline and during exposure to a food cue. Saliva will be collected during a baseline period and again while participants simulate eating a food item by focusing on its smell, taste, and texture. Saliva will be collected in graduated tubes and weighed to quantify salivary output. Change in salivation from baseline to food cue exposure will be compared across groups.	During study participation, up to 2 weeks

Collaborators and Investigators

• Sponsor: Purdue University
• Investigators: Principal Investigator: Richard D Mattes, PhD, RD, MPH, Purdue University

Publications and helpful links

General Publications

• Kadouh H, Chedid V, Halawi H, Burton DD, Clark MM, Khemani D, Vella A, Acosta A, Camilleri M. GLP-1 Analog Modulates Appetite, Taste Preference, Gut Hormones, and Regional Body Fat Stores in Adults with Obesity. J Clin Endocrinol Metab. 2020 May 1;105(5):1552-63. doi: 10.1210/clinem/dgz140.

Study record dates

Study Major Dates

• Study Start (Actual): February 20, 2025
• Primary Completion (Actual): May 4, 2026
• Study Completion (Actual): May 4, 2026

Study Registration Dates

• First Submitted: May 14, 2026
• First Submitted That Met QC Criteria: May 20, 2026
• First Posted (Actual): May 28, 2026

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: appetite; taste; food preferences; olfaction; food craving; smell; GLP-1 receptor agonists; Food cue responsivity; Salivary response
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Nutrition Disorders; Overnutrition; Body Weight; Sensation Disorders; Olfaction Disorders; Pathological Conditions, Signs and Symptoms; Behavior; Nutritional and Metabolic Diseases; Signs and Symptoms; Behavior, Animal; Anosmia; Overweight; Obesity; Feeding Behavior; Food Preferences
• Other Study ID Numbers: IRB-2024 - 1407

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 maintained in de-identified form, and identifiers/code keys will be stored separately and destroyed according to the approved protocol. De-identified data may be used by the study team for approved secondary analyses, but individual participant data will not be made publicly available or shared externally.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No