Secondary outcomes included (i) post-bariatric surgery nutrient stimulated plasma levels of glucose dependent insulinotropic polypeptide (GIP), insulin and C-peptide in patients with and without hypoglycaemia, (ii) HbA1c, (iii) hypoglycaemic counter-regulatory hormones (cortisol, glucagon, adrenaline, noradrenaline) and (iv) gastric emptying data. This evidence concerns the gene GIP and Hypoglycemia.