A study investigating the influence of fat distribution, genetic susceptibility markers for type 2 diabetes (T2DM) and fat distribution, epigenetic and transcriptomic changes and gut hormone responses to a mixed meal on diabetes remission following bariatric surgery.

Bariatric surgery group

Inclusion Criteria:

• Males and females planning to undergo RYGB
• 18-80 years
• Type 2 diabetes mellitus or prediabetes
• Stable weight for at least 3 months
• Obese (BMI ≥30kg/m2)
• Eligible for surgery on the National Health Service (NHS) under The National Institute for Health and Care Excellence (NICE) 2014 criteria

Exclusion Criteria:

• Current pregnancy
• Inability to give informed consent
• Type 1 diabetes
• Low fasting C-peptide
• Secondary diabetes or absence of β-cell function
• Unable to undergo DEXA, cirrhosis, ascites, or other condition that may modify body fat composition e.g. underlying malignancy
• Current smoker
• Participation in another (interventional) trial within the last 3 months
• Unable to understand English

Healthy volunteers

Inclusion criteria:

• Aged 18-80 years
• Male or female
• Body mass index 19 - 25 kg/m2
• Stable weight for at least three months

Exclusion criteria:

• Abnormal glucose tolerance and fasting glucose
• History of any medical, or other condition, or use of any medications, including over-the-counter products, which, in the opinion of the investigators, would either interfere with the study
• Without access at home to a telephone, or other factor likely to interfere with ability to participate reliably in the study
• Pregnancy or breastfeeding
• Unable to maintain adequate contraception for the duration of the study
• Donated blood during the preceding 3 months or intention to do so before the end of the study
• Current smoker
• Participation in another trial within the last 3 months
• Unable to understand English

Up to 150 patients recruited to completion from Imperial Weight Centre. Up to 60 healthy volunteers