ObesityFGBNCT03091725
Postprandial Nutrient Homeostasis Before and After Weight Loss Induced by Low-calorie Diet or RYGB
A study testing Roux-en-Y gastric bypass surgery and Low-calorie diet in people with Obesity, run by Washington University School of Medicine at 1 site in United States.
Trial summary
The purpose of this study is to compare the metabolic responses to low-carbohydrate and standard-carbohydrate meals in African Americans and non-Hispanic White adults with obesity and the effect of weight loss induced by low-calorie diet (LCD) or Roux-en-Y gastric bypass (RYGB) on the metabolic responses to… Read more about this study
- Who is it for?
- Ages 25 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Obesity
- What is being tested?
- Roux-en-Y gastric bypass surgery and Low-calorie diet
- Type of treatment
- Surgery or procedure, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 25 Apr 2017to Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Surgery Group (RYGB):
- Males and Females
- Scheduled for RYGB surgery
- Body Mass Index 35-60 kg/m²
- Without Type 2 Diabetes (T2D)
- LCD group:
Show all 9Show fewer
- Males and Females
- Body Mass Index 35-60 kg/m²
- Without Type 2 Diabetes (T2D)
Who cannot join
- Regular use of tobacco products
- Previous intestinal resection
- Pregnant or breastfeeding
- Evidence of significant organ system dysfunction or disease other than obesity and T2D
- Use of any medication that might, in the opinion of the investigator, affect metabolic function
- Exercise ≥90 minutes per week
- Use or past use of hormone replacement therapy within the past 6 months
Trial locations and contacts
1 site in 1 country.
About this study
The purpose of this study is to compare the metabolic responses to low-carbohydrate and standard-carbohydrate meals in African Americans and non-Hispanic White adults with obesity and the effect of weight loss induced by low-calorie diet (LCD) or Roux-en-Y gastric bypass (RYGB) on the metabolic responses to low-carbohydrate and standard meals. Participants will consume: 1) a standard-carbohydrate meal (~49 g glucose) and 2) a low-carbohydrate (~3.4 g glucose) meal on separate study visits performed in a randomized order. We will evaluate the meals' effect before and after ~16-18% weight loss on postprandial i) insulin kinetics, ii) glucose kinetics iii) β-cell function; iv) plasma triglyceride and non-esterified fatty acid concentrations; v) plasma hormone concentrations; vi) plasma cytokine concentrations; vi) plasma metabolomics; and vii) adipose tissue transcriptomics.
- Conditions
- Obesity
- Being tested
- Roux-en-Y gastric bypass surgery, Low-calorie diet
- Keywords
- Obesity, Roux-en-Y gastric bypass (RYGB), Low calorie diet
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Roux-en-Y gastric bypass surgeryProcedure or surgery
Roux-en-Y gastric bypass surgery will be performed with post-weight loss testing performed after ~16-18% weight loss is achieved.
Low-calorie dietBehavioural
Subjects will meet with a dietitian and/or behaviorist over 4-6 months to lose ~16-18% of their body weight.
| Study group | Role | What they receive |
|---|---|---|
| RYGB group | Experimental | Subjects in this group are scheduled to undergo Roux-en-Y gastric bypass surgery and will be assessed after ~16-18% weight-loss Receives: Procedure: Roux-en-Y gastric bypass surgery |
| LCD Group | Active comparator | Subjects in this group will participate in a low-calorie diet intervention to achieve ~16-18% weight loss. Receives: Behavioral: Low-calorie diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Postprandial plasma insulin kinetics
Plasma insulin kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial plasma insulin kinetics
Plasma insulin kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Secondary outcomes (18)
Postprandial glucose kinetics
Plasma glucose kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial glucose kinetics
Plasma glucose kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
β-cell function
β-cell function will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
β-cell function
β-cell function will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial triglyceride concentrations
Plasma triglyceride concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial triglyceride concentrations
Plasma triglyceride concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial non-esterified fatty acid concentrations
Plasma non-esterified fatty acid concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial non-esterified fatty acid concentrations
Plasma non-esterified fatty acid concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial hormone concentrations
Plasma hormone concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial hormone concentrations
Plasma hormone concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial cytokine concentrations
Plasma cytokine concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial cytokine concentrations
Plasma cytokine concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial lipids
Plasma lipids will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal by using mass spectrometry.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial lipids
Plasma lipids will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal by using mass spectrometry.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial metabolites
Plasma metabolites will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal by using mass spectrometry.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial metabolites
Plasma metabolites will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal by using mass spectrometry.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Transcriptome in adipose tissue
The transcriptome (all RNA that are responsible for making proteins from DNA templates) will be evaluated by using RNA sequencing techniques in adipose tissue samples collected before and ~3h after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Transcriptome in adipose tissue
The transcriptome (all RNA that are responsible for making proteins from DNA templates) will be evaluated by using RNA sequencing techniques in adipose tissue samples collected before and ~3h after consuming a standard-carbohydrate or a low-carbohydrate meal.
Measured: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Mar 2017
- Study start25 Apr 2017
- Primary completion3 Jul 2025
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by Washington University School of MedicineThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Washington University School of Medicine
- Sponsor type
- University, hospital or other
- Collaborators
- Kilo Diabetes & Vascular Research Foundation
- Responsible party
- Sponsor
- Investigators
- Samuel Klein, MD, Principal investigator, Washington University School of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03091725
- Sponsor's protocol ID
- 201612107
- Acronym
- FGB
- Status last verified
- Aug 2026
- First submitted
- 13 Mar 2017
- Last updated
- 25 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Li E, Wang L, Wang D, Chi J, Lin Z, Smith GI, Klein S, Cohen P, Rosen ED. Control of lipolysis by a population of oxytocinergic sympathetic neurons. Nature. 2024 Jan;625(7993):175-180. doi: 10.1038/s41586-023-06830-x. Epub 2023 Dec 13.
PubMed 38093006
Study at a glance
From the registry record, last updated by the sponsor on 25 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Postprandial Nutrient Homeostasis Before and After Weight Loss Induced by Low-calorie Diet or RYGB
- ClinicalTrials.gov ID
- NCT03091725
- Acronym / sponsor ID
- FGB / 201612107
- Conditions
- Obesity
- Keywords
- Obesity, Roux-en-Y gastric bypass (RYGB), Low calorie diet
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Washington University School of MedicineUniversity, hospital or other
- Collaborators
- Kilo Diabetes & Vascular Research Foundation
- Study start
- 25 Apr 2017 (actual)
- Primary completion
- 3 Jul 2025 (actual)
- Study completion
- Dec 2026 (estimated)
- First posted
- 27 Mar 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to compare the metabolic responses to low-carbohydrate and standard-carbohydrate meals in African Americans and non-Hispanic White adults with obesity and the effect of weight loss induced by low-calorie diet (LCD) or Roux-en-Y gastric bypass (RYGB) on the metabolic responses to low-carbohydrate and standard meals. Participants will consume: 1) a standard-carbohydrate meal (~49 g glucose) and 2) a low-carbohydrate (~3.4 g glucose) meal on separate study visits performed in a randomized order. We will evaluate the meals' effect before and after ~16-18% weight loss on postprandial i) insulin kinetics, ii) glucose kinetics iii) β-cell function; iv) plasma triglyceride and non-esterified fatty acid concentrations; v) plasma hormone concentrations; vi) plasma cytokine concentrations; vi) plasma metabolomics; and vii) adipose tissue transcriptomics.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| RYGB group | Experimental | Procedure: Roux-en-Y gastric bypass surgerySubjects in this group are scheduled to undergo Roux-en-Y gastric bypass surgery and will be assessed after ~16-18% weight-loss |
| LCD Group | Active comparator | Behavioral: Low-calorie dietSubjects in this group will participate in a low-calorie diet intervention to achieve ~16-18% weight loss. |
Who may qualify
- Ages
- 25 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Males and Females
- Scheduled for RYGB surgery
- Body Mass Index 35-60 kg/m²
- Without Type 2 Diabetes (T2D)
- Males and Females
Key exclusion criteria (7 listed)
- Regular use of tobacco products
- Previous intestinal resection
- Pregnant or breastfeeding
- Evidence of significant organ system dysfunction or disease other than obesity and T2D
- Use of any medication that might, in the opinion of the investigator, affect metabolic function
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Roux-en-Y gastric bypass surgeryRoux-en-Y gastric bypass surgery will be performed with post-weight loss testing performed after ~16-18% weight loss is achieved. | Procedure or surgery | RYGB group |
| Low-calorie dietSubjects will meet with a dietitian and/or behaviorist over 4-6 months to lose ~16-18% of their body weight. | Behavioural | LCD Group |
Primary outcome
Postprandial plasma insulin kinetics
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Plasma insulin kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Postprandial plasma insulin kinetics
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Plasma insulin kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
18 secondary outcomes
Postprandial glucose kinetics
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial glucose kinetics
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
β-cell function
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
β-cell function
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial triglyceride concentrations
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial triglyceride concentrations
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial non-esterified fatty acid concentrations
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial non-esterified fatty acid concentrations
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial hormone concentrations
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial hormone concentrations
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial cytokine concentrations
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial cytokine concentrations
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial lipids
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial lipids
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Postprandial metabolites
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Postprandial metabolites
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Transcriptome in adipose tissue
Time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)
Transcriptome in adipose tissue
Time frame: After 16-18% weight loss induced by LCD or RYGB (~4-6 months)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Aug 2026.
- Derived from this study: PubMed 38093006Li E, Wang L, Wang D, Chi J, Lin Z, Smith GI, Klein S, Cohen P, Rosen ED. Control of lipolysis by a population of oxytocinergic sympathetic neurons. Nature. 2024 Jan;625(7993):175-180. doi: 10.1038/s41586-023-06830-x. Epub 2023 Dec 13.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Samuel Klein, MD principal investigator
Washington University School of Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Roux-en-Y gastric bypass surgery and Low-calorie diet in people with Obesity, run by Washington University School of Medicine at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 25 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Postprandial plasma insulin kinetics (time frame: Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03091725, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Aug 2026.