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

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

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.

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.

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