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

NCT03091725 | Active Not Recruiting DMC

• 1 other identifier: 201612107
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

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.

Conditions

Obesity

Keywords

Obesity; Roux-en-Y gastric bypass (RYGB); Low calorie diet

Outcome Measures

Primary Outcomes (2)

• 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.

  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.

  After 16-18% weight loss induced by LCD or RYGB (~4-6 months)

Secondary Outcomes (18)

• Postprandial glucose kinetics

  Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)

• Postprandial glucose kinetics

  After 16-18% weight loss induced by LCD or RYGB (~4-6 months)

• β-cell function

  Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)

• β-cell function

  After 16-18% weight loss induced by LCD or RYGB (~4-6 months)

• Postprandial triglyceride concentrations

  Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity)

Study Arms (2)

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

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.

Behavioral: Low-calorie diet

Interventions

Roux-en-Y gastric bypass surgery PROCEDURE

Roux-en-Y gastric bypass surgery will be performed with post-weight loss testing performed after \~16-18% weight loss is achieved.

RYGB group

Low-calorie diet BEHAVIORAL

Subjects will meet with a dietitian and/or behaviorist over 4-6 months to lose \~16-18% of their body weight.

LCD Group

Eligibility Criteria

• Age: 25 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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)

You may not qualify if:

• 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

Sponsors & Collaborators

• Washington University School of Medicine: lead
• Kilo Diabetes & Vascular Research Foundation: collaborator

Study Sites (1)

Beth Henk

St Louis, Missouri, 63110, United States

Location

MeSH Terms

Conditions

Obesity

Interventions

Caloric Restriction

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Energy Intake; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Samuel Klein, MD

  Washington University School of Medicine

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 13, 2017
• First Posted: March 27, 2017
• Study Start: April 25, 2017
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: March 17, 2026

Record last verified: 2026-03

Locations

US (1)