GCG and B cell deficiency: Lifestyle interventions such as weight loss and exercise reduce insulin resistance19,20, whereas reducing dietary sugar and glycaemic load might benefit those with β-cell deficiency and/or incretin deficits; metformin reduces hepatic glucose production, acarbose prevents absorption of dietary carbohydrates in the small intestine, thiazolidenediones are powerful insulin sensitizers, and GLP-1 agonists augment β-cell insulin secretion and reverse insulin resistance via weight loss.