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NCT Number: NCT07178704

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

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. In patients who undergo a routine endoscopy in advance of weight loss surgery a small sample of gut tissue will be collected to identify the expression (activity) of genes in their DNA.

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Key information

Conditions

Bariatric Surgery Patients Atrophy Muscular Atrophy Nervous System Diseases Neurologic Manifestations Neuromuscular Manifestations Pathological Conditions, Anatomical Pathological Conditions, Signs and Symptoms Sarcopenia Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

The University of Texas Medical Branch

Galveston, Texas, 77555, United States

Location status: Recruiting

Location contact

Emily J Lantz, PhD

CONTACT

[email protected]

409-772-0643

Emily J Lantz, PhD

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

(Bariatric Surgery Patients):

  • Age: 18 to 65 years at time of consent
  • BMI: 35-65 kg.m-2
  • Scheduled to undergo bariatric surgery at UTMB
  • All races and ethnic backgrounds
  • Ability to speak and read English
  • Subject has provided informed consent in a manner approved by the IRB and is willing and able to comply with the trial procedures.

Exclusion criteria

(Bariatric Surgery Patients):

  • Fails the medical criteria for bariatric surgery.
  • Anemia (hematocrit < 33 % or donated blood in the past 12 weeks.)
  • Recent (5 years or less) history of cancer
  • Systemic steroids or immunosuppressant use for 8 or more consecutive days in the past 6 months, or any use of anabolic steroids or growth hormones in the same period.
  • Body mass index < 35 or > 65 kg.m-2.
  • Acute infectious disease or chronic infection.
  • Pregnancy or breast-feeding.
  • Any medical condition that, in the opinion of the investigator, would place the subject at increased risk for participation.
  • History of prior non-compliance that would, in the opinion of the investigator, make it difficult for the subject to comply with the study procedures or follow the investigator's instructions.
  • Concurrent participation in another research study.
  • Use of an investigational agent in the 30 days prior to signing informed consent.

Treatment and study plan

Primary outcomes

  1. Body composition

    Time frame: 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.

Secondary outcomes

  1. Dietary Protein Intake

    Time frame: 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.

  2. Body weight

    Time frame: 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.

  3. Association between foregut gene expression and degree of weight reduction

    Time frame: 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.

  4. Handgrip Strength

    Time frame: 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.

  5. Energy Intake

    Time frame: 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Emily J Lantz, PhD

CONTACT

[email protected]

409-772-0643

Sponsors and collaborators

Lead sponsor

The University of Texas Medical Branch, Galveston

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Sep 17, 2025
Registry last updated
Jul 10, 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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