Glycemic Index

Measuring How Foods Affect Blood Sugar

The Glycemic Index (GI) is a scale that ranks carbohydrate-containing foods by how quickly they raise blood sugar levels compared to pure glucose. High-GI foods (white bread, sugar, white rice) cause rapid spikes, while low-GI foods (most vegetables, nuts) produce gentler rises. However, the GI has significant limitations: it doesn't account for portion size (Glycemic Load does), it measures single foods eaten alone (rarely how we eat), and it can be misleading—some high-GI foods like watermelon have little actual carbohydrate. For people with diabetes or insulin resistance, focusing on total carbohydrate amount and choosing whole, unprocessed foods often matters more than obsessing over GI rankings.