The Metabolic and Genetic Drivers of Body Composition Changes Following Weight Loss Surgery

Not yet recruiting

• Conditions: Bariatric Surgery Patients

• Registration Number: NCT07178704
• Lead Sponsor: The University of Texas Medical Branch, Galveston

Brief Summary

Weight loss surgery is very good at reducing body weight but it can also cause the loss of both muscle and strength. Some patients undergoing weight loss surgery do not achieve their weight loss goals and regain the weight they lost. When this occurs, the loss of muscle and strength combined with the regain of weight can impact the individual's quality of life and ability to remain active and mobile.

The purpose of this study is to understand the behavioral, biological, and genetic factors that influence the success of weight loss surgery and its impact on muscle mass.

Bariatric surgery patients participating in the trial will be monitored prior to, and for a year following weight loss surgery, with data collected about their eating habits, hand grip strength, and the loss of fat, muscle, and body weight following surgery. Some patients will be additionally invited to undergo detailed metabolic assessment, where we will measure how their body uses nutrients it consumes, the composition of their body (e.g. how much lean and fat tissue they have and where it is stored), identify the bacteria living in their gut, and determine their physical performance. In all patients a small sample of gut tissue will be collected at a routine endoscopy performed in advance of weight loss surgery to identify the expression (activity) of genes in their DNA.

Healthy subjects will also be recruited to allow us to compare between healthy weight individuals and those undergoing weight loss surgery. On a single occasion, the healthy volunteers will undergo the same detailed metabolic assessment performed in patients as described above. We will not examine the bacteria living in the gut of the healthy volunteers, nor will we collect gut tissue from these individuals.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2025-08-22
• Status Verified: 2025-09
• Study Start: 2025-09-01
• Study First Submitted QC: 2025-09-10
• Last Update Submitted: 2025-09-10
• Study First Posted: 2025-09-17
• Last Update Posted: 2025-09-17
• Primary Completion: 2027-02
• Study Completion: 2027-08-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 110

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Whole-body Protein Turnover Rates	Measured at baseline in both healthy volunteers & patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Whole-body protein turnover rates measured over a 48 hour period, accomplished via the consumption of a drink containing isotopically labelled (15N) alanine and the subsequent collection of urine for two days. Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.
Association between foregut gene expression and degree of weight reduction	A single occasion from tissue collected during the routine pre-operative upper endoscopy. (baseline)	Assessed only in patients. Gene expression of the foregut will be analyzed in tissue collected from patients during the routine pre-operative upper endoscopy. Subsequently, participants will be stratified into those achieving: \<10%, 10-20%, or \>20% weight loss 12 months post-surgery, and differentially expressed genes between the three groups determined.

Secondary Outcome Measures

Name	Time	Method
Dietary Protein Intake	Measured at baseline in both healthy volunteers & patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Dietary protein intake will be determined by participants completing three-day food diaries. This will be performed on a single occasion in healthy volunteers and up to three occasions in bariatric patients undergoing metabolic assessment.
Body weight	Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Body weight will be determined using digital scales (in kg). Procedures will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients.
Body composition	Measured at baseline in both healthy volunteers & bariatric surgery patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Body composition will be determined in patients by whole-body bioelectrical impedance. Regional body composition will be additionally assessed in healthy volunteers and bariatric surgery patients undergoing metabolic assessment via whole-body dual-energy x-ray absorptiometry (DXA) imaging. Procedures will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.
Short Physical Performance Battery Test	Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Assessed using the established short physical performance battery (SPPB) test. Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.
Handgrip Strength	Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Assessed using a handgrip dynamometer (in kg). Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients.
Physical Activity levels (accelerometry)	Measured at baseline in both healthy volunteers & bariatric surgery patients. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Assessed by having individuals wear an accelerometer for up to 7 days, allowing step counts and energy expenditure to be determined. Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.
Energy Intake	Measured at baseline in both healthy volunteers & bariatric surgery patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Energy intake assessed via the completion of a 3-day food diary. Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.
Energy Expenditure	Measured at baseline in both healthy volunteers & bariatric surgery patients undergoing metabolic assessment. The latter will undergo repeat assessment on two further occasions across a 1 year period post surgery.	Energy expenditure will be determined at rest via indirect calorimetry. Will be performed on a single occasion in healthy volunteers and up to three times in bariatric patients undergoing metabolic assessment.

Trial Locations

Locations (1)

The University of Texas Medical Branch; 🇺🇸 Galveston, Texas, United States