The Glycemic Index (GI) is a ranking system that measures how quickly carbohydrate-containing foods raise blood sugar levels. Foods are scored on a scale from 0 to 100, with pure glucose having a GI of 100. Low-GI foods, such as whole grains and legumes, are digested slowly, leading to gradual increases in blood sugar, while high-GI foods, like sugary snacks and white bread, cause rapid spikes. Understanding the GI can help individuals make healthier food choices, especially for those managing conditions like diabetes. By selecting low-GI options, people can maintain more stable energy levels and improve overall health.