Postprandial Nutrient Homeostasis Before and After Weight Loss Induced by Low-calorie Diet or RYGB

Not Applicable

Recruiting

• Conditions: Obesity
• Interventions: Procedure: Roux-en-Y gastric bypass surgery; Behavioral: Very low-calorie diet

• Registration Number: NCT03091725
• Lead Sponsor: Washington University School of Medicine

Brief 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 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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2017-03-13
• Study First Submitted QC: 2017-03-21
• Study First Posted: 2017-03-27
• Study Start: 2017-04-25
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-10
• Last Update Posted: 2025-03-13
• Primary Completion: 2025-12
• Study Completion: 2026-07

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

Surgery Group (RYGB):

• Males and Females
• Scheduled for RYGB surgery
• Body Mass Index 35-60 kg/m²
• Without Type 2 Diabetes (T2D)

LCD group:

• Males and Females
• Body Mass Index 35-60 kg/m²
• Without Type 2 Diabetes (T2D)

Exclusion Criteria

• 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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
RYGB group	Roux-en-Y gastric bypass surgery	Subjects in this group are scheduled to undergo Roux-en-Y gastric bypass surgery and will be assessed after 16-18% weight-loss
VLCD Group	Very low-calorie diet	Subjects in this group will participate in a very low-calorie diet intervention to obtain a 16-18% weight loss.

Primary Outcome Measures

Name	Time	Method
Postprandial plasma insulin kinetics	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.

Secondary Outcome Measures

Name	Time	Method
Postprandial non-esterified fatty acid concentrations	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	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.
Postprandial cytokine concentrations	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	Plasma cytokine concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Postprandial lipids	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	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.
Postprandial metabolites	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	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.
Postprandial glucose kinetics	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	Plasma glucose kinetics will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
β-cell function	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	β-cell function will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Postprandial triglyceride concentrations	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	Plasma triglyceride concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.
Transcriptome in adipose tissue	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	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.
Postprandial hormone concentrations	After 16-18% weight loss induced by LCD or RYGB (~4-6 months)	Plasma hormone concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal.

Trial Locations

Locations (1)

Beth Henk; 🇺🇸 Saint Louis, Missouri, United States