GCG and type 2 diabetes mellitus: Therefore, the aim of the Impact of Metabolic surgery on Pancreatic, Renal, and cardiOVascular hEalth in youth with type 2 diabetes (IMPROVE-T2D) study was to determine the early effect of VSG on glycemia (primary outcome), SI, insulin secretion, diabetes medication use, substrate oxidation, and the incretin response to feeding in youth-onset type 2 diabetes before and 3 months after undergoing VSG.