MRI scanning will be carried out supine on either a 1.5T or 3.0 T Philips Achieva MRI scanner (Philips Healthcare, Best, The Netherlands) depending on availability. Fasting and post-prandial plasma tests: On the morning of the test, a 10 ml fasting blood sample will be drawn in aprotonin/EDTA tubes (BD-361017, BD Diagnostics, Oxford). Samples will be measured every 45 min to 270 min. Samples will be centrifuged at 4000 rpm for 5 min and stored on ice. Measurement of plasma peptides: All EC peptides (GLP-1, PYY) will be analysed through ELISA techniques (Millipore, UK). Serum CCK will be measured by RIA (Euro Diagnostic Products, Sweden). Total EC plasma peptide response will be presented as per individual time points and compositely as area under the curve (AUC).