Gastrointestinal Responses to Dietary Fibers in Adults on Weight Loss Medications

Study start date: May 29, 2025

Inclusion Criteria: 1. Male or female 25 to 64 years of age, inclusive. There will be approximately equal numbers of men and women. 2. Individual has a self-reported BMI of 18.5 to 39.9 kg/m2, inclusive. 3. Individual has been taking tirzepatide (≥10 mg weekly injection), semaglutide (≥2.0 mg weekly injection), or liraglutide (≥2.4 mg daily injection) for at least 4 weeks and plans to continue to take it throughout the duration of the study. 4. Individual has attained a high school diploma or a General Educational Development (GED) equivalent. 5. Individual has not participated in another research study within 30 days of the screening visit. 6. Individual is willing and able to undergo the scheduled study procedures. 7. Individual understands the study procedures and signs forms documenting informed consent to participate in the study and authorization for release of relevant protected health information to the study Investigator. Exclusion Criteria: 1. Individual has a clinically significant medical condition that, in the opinion of the Investigator, could interfere with the interpretation of the study results. Health conditions may include history or presence of clinically important GI, cardiac, renal, hepatic, endocrine, pulmonary, biliary, pancreatic, or neurological disorders that may affect the participant's ability to adhere to the study protocol and/or affect study outcomes, in the judgment of the Investigator. Clinically important GI conditions included but are not limited to: inflammatory bowel disease, irritable bowel syndrome, gastroparesis, clinically important lactose intolerance. 2. Individual habitually consumes \>8 g fiber per 1000 kcal per day. 3. Individual had a recent (within two weeks of screening) episode of acute GI illness such as nausea, vomiting, or diarrhea. 4. Individual has a history of frequent diarrhea or constipation prior to beginning GLP-1 receptor agonist that, in the opinion of the Investigator, could interfere with the interpretation of the study results. 5. Individual has a history of stomach or GI surgery (e.g., gastric bypass, cholecystectomy) that in the opinion of the Investigator, could interfere with evaluation of the study outcomes. 6. Individual uses medications (over-the counter or prescription) or dietary supplements known to influence gastrointestinal motility including laxatives, enemas, or suppositories; prokinetic drugs; anti-diarrheal agents, anti-spasmotics; fiber supplements; and prebiotic and probiotic supplements (Appendix 6). A 14-day washout phase prior to day 1 is allowed for participants taking any of these products. 7. Daily use of non-steroidal anti-inflammatory drugs (NSAIDs). 8. Individual has a history of cancer in the prior 2 years, except non-melanoma skin cancer or carcinoma in situ of the cervix. 9. Individual has a history of a diagnosed eating disorder (e.g., anorexia or bulimia nervosa). 10. History of any major trauma or major surgical event within 2 months of visit 1. 11. Use of tobacco/nicotine products (e.g., cigarette smoking, vaping, chewing tobacco) within 12 months of visit 1. 12. Use of hemp/marijuana products within 12 months of visit 1. Occasional use (e.g., once or twice a month) within 12 months of visit 1 is allowed but requires at least a 14-day washout prior to day 1 and the participant must be willing to refrain from use during the study. 13. Individual is a female who is pregnant, planning to be pregnant during the study period, lactating, or is of childbearing potential and is unwilling to commit to the use of a medically approved form of contraception throughout the study period. 14. Individual has an allergy, sensitivity, or intolerance to any foods. 15. Individual has extreme dietary habits (e.g., vegan, Atkins diet, etc.). 16. Individual has signs or symptoms of an active infection of clinical significance or has taken antibiotics within 10 days prior to any visit (washout is permitted for re-scheduling of a visit). 17. Individual has a current or recent history (past 12 months of screening) or strong potential for illicit drug or excessive alcohol intake defined as \>14 drinks per week (1 drink = 12 oz beer, 5 oz wine, or 1.5 oz hard liquor). 18. Individual has been exposed to any non-registered drug product within 30 days prior to screening. 19. Individual has a condition the Investigator believes would interfere with his or her ability to provide informed consent, comply with the study protocol, or which might confound the interpretation of the study results or put the person at undue risk.