Effects of Very Low-calorie Diet Versus Bariatric Surgery on Body Composition and Gut Microbiota Pattern

Not Applicable

• Conditions: Obesity
• Interventions: Other: Very low-calorie diet; Procedure: Bariatric surgery

• Registration Number: NCT05459675
• Lead Sponsor: Mahidol University

Brief Summary

Obesity is a chronic disease characterized by the excessive accumulation of fat in body and it continues to be a major public health problem worldwide. Treatment options for obesity include lifestyle modification, pharmacotherapy and bariatric surgery. Bariatric surgery is a highly effective treatment for obesity and results in rapid and sustained weight loss. Also, it significantly alters gut microbiota composition and function. A very low-calorie diet (VLCD) is a rapid weight loss program which calorie intake is severely restricted (\< 800 kcal/day). It has been shown to be very effective to induce rapid weight loss and result in comorbidities resolution similar to bariatric surgery. Therefore, this study was aimed to study the effects of 12-week VLCD compare to bariatric surgery (Laparoscopic Roux-en-Y gastric bypass (LRYGB) or Laparoscopic Sleeve Gastrectomy (LSG)) on weight loss, body composition, gut microbiota pattern and other metabolic parameters.

Detailed Description

The study will include obese patients (body mass index; BMI ≥ 37.5 kg/m2 or BMI ≥ 32.5 kg/m2 with comorbidities), aged 15-65 years at Ramathibodi Hospital, Thailand. The VLCD group will received total diet replacement for 12 weeks and the bariatric surgery group will undergo LRYGB or LSG. Study participants in both groups will be matched according to their age, sex, body mass index (BMI) and diabetic status. Body weight reduction and body composition, gut microbiota pattern, liver stiffness and steatosis, glycemic and other metabolic parameters (glucose, insulin, c-peptide, lipid profile, liver function test, kidney function test, complete blood count, electrolyte blood test, thyroid function tests, serum ketone and adiponectin), health-related quality of life, depression score and twenty-four-hour diet recall and physical activity will be assessed at baseline and at month 1, 3, 6, 9 and 12.

Study Timeline

• Study First Submitted: 2022-06-02
• Study First Submitted QC: 2022-07-14
• Study First Posted: 2022-07-15
• Study Start: 2022-07-20
• Primary Completion: 2022-11-20
• Status Verified: 2023-07
• Last Update Submitted: 2023-07-03
• Last Update Posted: 2023-07-05
• Study Completion: 2023-07-20

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 54

Inclusion Criteria

• Aged 15-65 years
• Male or female
• Body mass index ≥ 32.5 kg/m2 with obesity related co-morbidity
• Body mass index ≥ 37.5 kg/m2 with or without an obesity related co-morbidity

Exclusion Criteria

• End stage disease such as cancer, cirrhosis Child-Pugh C, critical/acute illness
• Type 1 diabetes mellitus
• Recent eGFR < 30 ml/min/1.73 m2
• Weight loss ≥ 5% in the previous 3 months
• Use of antibiotics in the previous 1 month
• Use of probiotic or prebiotic supplement in form of tablet or sachet in the previous 14 days
• Current treatment with anti-obesity drugs
• Pregnancy or breast feeding
• Substance abuse
• Uncontrolled psychiatric disorder and eating order
• History of allergy to any components in meal replacement product or whey protein product
• Unable to give informed consent

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Very low-calorie diet	Very low-calorie diet	Patients in the very low-calorie diet group will be prescribed a very low-calorie diet (meal replacement) for 12 weeks, then the patients will be monitored up to 1 year
Bariatric surgery	Bariatric surgery	Patients in the bariatric surgery group will be undergone bariatric surgery LRYGB and will be follow-up according the current guideline

Primary Outcome Measures

Name	Time	Method
Changes in body weight	From baseline to 12 weeks	Weight in kg

Secondary Outcome Measures

Name	Time	Method
Body Composition	From baseline to 12 weeks	The percentage of body fat and skeleton muscle mass
Gut microbiota pattern	From baseline to 12 weeks	Measured by 16S ribosomal RNA (rRNA) gene sequencing on the fecal samples
Liver steatosis	From baseline to 12 weeks	Measured by FibroScan® instrument
Fasting insulin	From baseline to 12 weeks	Measured in μIU/l
Insulin resistance	From baseline to 12 weeks	Measured by the homeostatic model of insulin resistance (HOMA-IR)
Liver stiffness	From baseline to 12 weeks	Measured by FibroScan® instrument
Fasting plasma glucose	From baseline to 12 weeks	Measured in mg/dl
Hemoglobin A1c	From baseline to 12 weeks	Measured in %
Triglyceride	From baseline to 12 weeks	Measured in mg/dl
Depression	From baseline to 12 weeks	Measured by the PHQ-9 questionnaire
Blood pressure	From baseline to 12 weeks	Systolic and diastolic blood pressure
HDL-cholesterol	From baseline to 12 weeks	Measured in mg/dl
Health-related quality of life	From baseline to 12 weeks	Measured by the EQ-5D-5L questionnaire
Total cholesterol	From baseline to 12 weeks	Measured in mg/dl
LDL-cholesterol	From baseline to 12 weeks	Measured in mg/dl

Trial Locations

Locations (1)

Faculty of Medicine Ramathibodi Hospital Mahidol University; 🇹🇭 Bangkok, Thailand