The glycemic index (GI) is a dietary tool used to classify carbohydrate-containing foods according to their effect on blood glucose levels. Foods are categorized as low, medium, or high GI based on the rate at which their carbohydrates are absorbed compared with glucose. First introduced in 1981, the GI is supported by a well-established and reliable methodology. GI testing is standardized by the International Organization for Standardization (ISO), which specifies the procedures used to determine a food’s GI value.

Although GI is a long-established nutritional concept, it has recently experienced renewed relevance and consumer interest. This resurgence is driven by several interconnected factors, including the rising prevalence of metabolic conditions such as type 2 diabetes, prediabetes, and insulin resistance, for which postprandial glucose control is critical. In conjunction, the growth of personalized nutrition and the increasing use of continuous glucose monitors (CGMs) have heightened awareness of how individual foods influence blood glucose levels in real time and empowered individuals to become more actively involved in monitoring their glucose levels.

At the same time, nutrition guidance has shifted away from an exclusive focus on calorie intake toward a broader emphasis on carbohydrate quality, fiber content, and metabolic effects. Clinical research continues to support this approach, with GI-based dietary patterns demonstrating benefits for glycemic control, lipid profiles, and weight management.

As metabolic health priorities, glucose-monitoring technologies, and food formulations continue to evolve, the glycemic index remains a practical and increasingly valuable tool for understanding how foods affect the body.