Glycemic load (GL) accounts for both the glycemic index of a food AND the actual carb portion. It's the better real-world metric than GI alone.
Mechanism: A high-GI food in a small portion may have a low GL. Watermelon has a high GI but low GL per serving. GL predicts the meal's actual blood-glucose excursion better.
Use case: Aim for low-to-moderate GL meals (<20 per meal) most of the time. Pair carbs with protein, fat, and fiber to flatten the curve.
Caveats: Individual response varies. What's a 30-point spike for you may be a 60-point spike for someone else. CGM data beats lookup tables.