A numerical ranking system used to measure how quickly and significantly a carbohydrate-containing food raises blood glucose levels compared to a reference food, usually pure glucose or white bread. Foods are scored on a scale of 0 to 100. High-GI foods (70 or above) are rapidly digested and absorbed, causing sharp spikes in blood sugar and insulin, while low-GI foods (55 or below) produce a slower, more sustained rise.
Utilizing the Glycemic Index is a key strategy in managing postprandial (after-meal) glycemia. Diets focusing on low-GI foods—such as non-starchy vegetables, legumes, and certain fruits—help prevent the 'glycemic rollercoaster' of energy highs and lows, thereby reducing the risk of developing type 2 diabetes and aiding in weight management.
The definitive guide by Russell Clark, FNP-C, APRN