What is the difference between glycemic index and glycemic load?

• A. Glycemic index measures rise in blood glucose after 50 g carbohydrate; glycemic load accounts for carbohydrate amount in a serving.
• B. Glycemic index measures insulin response; glycemic load measures lipid impact.
• C. Glycemic index is for fats; glycemic load is for proteins.
• D. Glycemic index is a tissue glucose uptake metric; glycemic load is hepatic glucose production.

Answer: (B)

The key idea is how each measure translates a carbohydrate’s impact into real-world response. Glycemic index shows how quickly blood glucose rises after consuming a fixed amount of carbohydrate from a food, using a standard reference to compare foods. It focuses on the speed of the glucose spike, not how much you eat. Glycemic load builds on that by taking into account how much carbohydrate is actually in a typical serving, calculated as GI times the grams of carbohydrate per serving divided by 100. This makes GL a more practical gauge of the actual glucose impact you’d see from a real meal.

So a food can have a high glycemic index but a low glycemic load if the serving size contains little carbohydrate, leading to a modest overall glucose rise. Conversely, a food with a moderate GI can have a high GL if you eat a large portion, resulting in a bigger glucose impact. Both measures relate to blood glucose, not directly to insulin response or lipid effects, which is why they’re used to predict glucose responses rather than other metabolic outcomes.