Obesity
Conditions
Keywords
Obesity, Roux-en-Y gastric bypass (RYGB), Low calorie diet
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.
Interventions
PROCEDURERoux-en-Y gastric bypass surgery
Roux-en-Y gastric bypass surgery will be performed with post-weight loss testing performed after \~16-18% weight loss is achieved.
BEHAVIORALLow-calorie diet
Subjects will meet with a dietitian and/or behaviorist over 4-6 months to lose \~16-18% of their body weight.
Sponsors
Washington University School of Medicine
Kilo Diabetes & Vascular Research Foundation
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
25 Years to 65 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial plasma insulin kinetics | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial glucose kinetics | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | 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 | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | 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 | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | Plasma triglyceride concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal. |
| Postprandial non-esterified fatty acid concentrations | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | 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 hormone concentrations | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | Plasma hormone concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal. |
| Postprandial cytokine concentrations | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | Plasma cytokine concentrations will be assessed in blood samples collected before and after consuming a standard-carbohydrate or a low-carbohydrate meal. |
| Postprandial lipids | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | 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 | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | 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. |
| Transcriptome in adipose tissue | Baseline only (cross-sectional comparison of metabolic responses in African American and non-Hispanic White adults with obesity) | 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. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORSamuel Klein, MD
Washington University School of Medicine
Outcome results
None listed