Glycemic Index (GI)
Definition
A numerical ranking system (0-100) that measures how quickly a carbohydrate-containing food raises blood glucose levels after consumption. Pure glucose is the reference food with a GI of 100. Foods are classified as Low GI (≤55), Medium GI (56-69), or High GI (≥70).
Why It Matters
High-GI foods cause rapid blood sugar spikes followed by crashes, triggering hunger, fatigue, and cravings. Consistently consuming high-GI foods is linked to insulin resistance, type 2 diabetes, cardiovascular disease, and weight gain. However, GI alone can be misleading because it doesn't account for portion size — that's where Glycemic Load (GL) becomes more useful.
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Related Terms
Glycemic Load (GL)
InformationalA measure that accounts for both the quality (Glycemic Index) and quantity (grams of carbohydrate per serving) of carbohydrates in a food. Calculated as: GL = (GI × grams of carbs per serving) ÷ 100. Classified as Low (≤10), Medium (11-19), or High (≥20).
Maltodextrin
CautionA highly processed white powder made from corn, rice, potato, or wheat starch. Despite being classified as a complex carbohydrate, it is broken down so aggressively during processing that its glycemic index (GI 85-105) often exceeds that of table sugar (GI 65).