The Glycemic Index (GI) compares foods based on how rapidly they raise blood sugar after eating. Pure glucose = 100 (reference).
GI Categories
- Low GI (≤55): Oats, legumes, most fruits — steady energy
- Medium GI (56–69): Brown rice, whole wheat bread
- High GI (≥70): White bread, white rice, potatoes — rapid spike
Glycemic Load
GI doesn't account for portion size. Glycemic Load (GL) = GI × carbs per serving / 100. Watermelon has high GI (72) but low GL (4) because it's mostly water.