Glycemic Index (GI)
Definition
A ranking system from 0 to 100 that measures how quickly a carbohydrate-containing food raises blood sugar levels after eating.
The glycemic index ranks foods on a scale of 0 to 100 based on how rapidly they increase blood glucose levels. Foods are classified as low GI (55 or less), medium GI (56-69), or high GI (70 or above). Pure glucose has a GI of 100 and serves as the reference point.
Low-GI foods like oats, legumes, and most vegetables cause a gradual rise in blood sugar and sustained energy. High-GI foods like white bread, candy, and potatoes cause rapid spikes followed by crashes. Choosing lower GI foods can help manage blood sugar, improve satiety, and reduce the risk of type 2 diabetes.
The glycemic load (GL) refines this concept by accounting for the portion size eaten. A food might have a high GI but a low GL if you eat a small amount. Watermelon, for example, has a high GI but a low GL because a typical serving contains relatively few carbohydrates.
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Related Calculators
Related Terms
Carbohydrate
healthOne of the three macronutrients, providing 4 calories per gram, serving as the body's primary and preferred source of energy.
Dietary Fiber
healthA type of carbohydrate that the body cannot fully digest, essential for digestive health, blood sugar regulation, and cholesterol management.
Macronutrients
healthThe three categories of nutrients that provide calories and energy: protein, carbohydrates, and fat, needed by the body in large quantities.
Calorie
healthA unit of energy used to measure the energy content of food and beverages and the energy expenditure of physical activities.
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