INS and Hypoglycemia: A supervised fast was conducted and terminated after 7 h due to the onset of retrograde amnesia, with a glucose level of 1.5 mmol/L, an insulin level of 74.97 mU/L (reference range 2.6–24.9 mU/L), and a C-peptide of 1.37 nmol/L (reference range 0.27–1.27), confirming endogenous hyperinsulinemic hypoglycemia.