The Ibaguner Insulinemic-Glycemic Discordance Index (IGDI): A Framework for Characterizing Postprandial

Postprandial metabolic risk is conventionally assessed using the Glycemic Index (GI) and the Insulinemic Index (II) as independent measures. However, the relationship between glucose and insulin responses carries additional information beyond either index alone. We propose the Insulinemic-Glycemic Discordance Index (IGDI), a framework that (i) defines reference-normalized GI and II from incremental areas under the curve, (ii) quantifies directional discordance D = II − GI, (iii) classifies foods into a four-quadrant model by magnitude and direction, and (iv) computes a composite Postprandial Metabolic Risk Score (PMRS) with explicit weights. The framework is testable, falsifiable, and designed for empirical refinement against clinical outcomes.