Low-calorie Diet and Body Composition Prior to Roux-en-Y Gastric Bypass

Study Overview
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Brief Summary
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Losing weight before undergoing Roux-en-Y gastric bypass (RYGB) surgery may reduce liver fat content and size thereby improving surgical outcomes. This study aims to investigate whether a 2-week or 6-week pre-operative liquid formula low-calorie diet (LCD) reduces liver fat further than a conventional food diet prior to RYGB using magnetic resonance imaging (MRI). The hypothesis is that the 2-week and 6-week liquid formula LCD will reduce liver fat further than the conventional food pre-operative diet.

Detailed Description
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The morbidly obese subjects (BMI higher then 40 kg/m2) were randomised and assessed at baseline (week 0). After 2 weeks on a low-calorie diet (LCD), participants underwent either Roux-en-Y gastric bypass (RYGB) or continued with a LCD for 4 weeks.The participants will reassess at week 6.

Official Title
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The Effect of a 2-week vs. 6-week Low-calorie Diet (LCD) Followed by Roux-en-Y Gastric Bypass (RYGB) on Body Composition and Surgery Outcomes in Obese Humans: a Dietary Intervention and Magnetic Resonance Imaging Study

Conditions
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Morbid Obesity, Liver Fat

Intervention / Treatment
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* Dietary Supplement: Liquid formula low-calorie diet (LCD)
* Procedure: Roux-en-Y gastric bypass (RYGB)
* Other: Control diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing Roux-en-Y gastric bypass at Imperial Weight Centre aged 18 to 60 years boby mass index of 35 to 55 kg/m2 Exclusion Criteria: Claustrophobia Pacemaker, metal implant, clips, implanted device, shrapnel or bullets, metal in eyes that precludes magnetic resonance imaging Current pregnancy or breast feeding for females (as determined by a pregnancy test) A full term pregnancy within the last year for females Treatment with any medication that might affect the study outcomes Haemorrhagic disorders and anticoagulant treatment History of cancer, excluding skin cancer History of severe or multiple allergies, severe adverse drug reaction or leucopenia Smokers Regular drinkers of more than three units of alcohol daily History of, or current evidence of, abuse of alcohol or any drug substance, licit or illicit Regular intake of over-the-counter (OTC) medication (other than the occasional paracetamol/aspirin) Poor compliers or subjects unlikely to commit to the 26 week study duration Blood donation within the 12 week period before the initial study dose Use of monoamine oxidase inhibitors (MAOIs) as anti depressant

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 2-week LCD and Roux-en-Y gastric bypass (RYGB)<br>A 2-week liquid formula low-calorie diet (LCD) will be administered for 2 weeks prior to Roux-en-Y gastric bypass. The diet will provide 800kcal per day in the form of powdered milkshakes and soups | Dietary Supplement: Liquid formula low-calorie diet (LCD)<br>* The liquid formula low-calorie diet (LCD) will provide 800kcal/day from powdered milkshakes and soups. The diet will be provided by Cambridge Weight Plan.<br>* Other names: Cambridge Weight Plan;Procedure: Roux-en-Y gastric bypass (RYGB)<br>* Participant went through Roux-en-Y gastric bypass (RYGB) surgery<br>|
| Active Comparator: 6-week LCD<br>A 6-week liquid formula low-calorie diet (LCD) will be administered for 6 weeks prior to Roux-en-Y gastric bypass. The diet will provide 800kcal per day in the form of powdered milkshakes and soups | Dietary Supplement: Liquid formula low-calorie diet (LCD)<br>* The liquid formula low-calorie diet (LCD) will provide 800kcal/day from powdered milkshakes and soups. The diet will be provided by Cambridge Weight Plan.<br>* Other names: Cambridge Weight Plan;|
| Other: Control diet<br>1000 calorie diet | Procedure: Roux-en-Y gastric bypass (RYGB)<br>* Participant went through Roux-en-Y gastric bypass (RYGB) surgery<br>Other: Control diet<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Intra-hepatocellular Lipid Content (IHCL) Following the Pre-operative Diet | Intra-hepatocellular lipid content will be measured by magnetic resonance spectroscopy | at 2 weeks or 6 weeks depending on group | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Intra-hepatocellular Lipid Content (IHCL) Following Roux-en-Y Gastric Bypass | Intra-hepatocellular lipid content (IHCL) will be compared between groups at 1 month following Roux-en-Y gastric bypass | at 1-month following Roux-en-Y gastric bypass | 
| Change in Intra-hepatocellular Lipid Content (IHCL) Following Roux-en-Y Gastric Bypass | Intra-hepatocellular lipid content (IHCL) will be compared between groups at 6 months following Roux-en-Y gastric bypass | at 6 months following Roux-en-Y gastric bypass | 
| Complexity of Surgery | Complexity of surgery will be assessed by the surgeon at the time of surgery (either after 2 weeks for the Control group and 2-week LCD group or after 6 weeks for the 6-week LCD group) The complexity of the surgery was assessed through a score on a complexity scale based on questionnaires previously published by Anders Thorells and David Edholms groups (Edholm et al., 2011, Van Nieuwenhove et al., 2011). The scores (1-5) for 7 variables: exposure, bleeding, difficulty in dissection, difficulty in reconstruction, surgical judgment, technical demand and psychological stress were combined into a complexity of surgery score with a minimum of 7 (very little complexity) and a maximum of 35 (very high complexity). | at the time of surgery | 
| Operative Time | The operative time will be recorded at the time of surgery by the operating surgeon (either after 2 weeks for the Control group and 2-week LCD group or after 6 weeks for the 6-week LCD group) | at the time of surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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morbid obesity, gastric bypass, bariatrics, diet, caloric restriction, liver fat, appetite