Carbohydrate Guide
What is the glycemic index, and does it matter?
The glycemic index (GI) ranks how quickly a carbohydrate-containing food raises blood sugar compared to pure glucose.
How it works
Foods are scored on a 0–100 scale: high-GI foods (white bread, white rice, most sugary drinks) cause a fast, sharp rise in blood sugar, while low-GI foods (most legumes, oats, non-starchy vegetables) produce a slower, more gradual rise.[1] Several factors affect a food's GI beyond the carb itself: fiber content, how processed or ripe it is, and what it's eaten alongside.
The practical takeaway
- Pairing carbs with protein, fat, or fiber lowers the effective glycemic response of a meal, even if an individual ingredient has a high GI on its own
- GI isn't the whole picture — glycemic load (which factors in portion size) and overall diet quality matter at least as much as a single food's GI ranking
- It's most useful as a general pattern — favoring minimally processed, fiber-rich carb sources most of the time — rather than a strict food-by-food rulebook
Keep reading: Simple vs. complex carbs · What carbohydrates actually do · Why fiber matters