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Glycemic Index (GI)

Ranking of carbohydrate-containing foods by their effect on postprandial blood glucose relative to a reference (glucose or white bread = 100), measured as the incremental area under the 2-hour glucose curve.

Also: GI

GI captures carbohydrate quality (kinetics of digestion and absorption) but not quantity. Glycemic load (GL = GI × g carbohydrate / 100) accounts for both. Low-GI diets modestly improve glycemic control and lipids in diabetes but their relative importance versus total carbohydrate, fiber, and dietary pattern is contested. MNHD Ch 3 (Carbohydrates) treats GI as one input among many.

How each textbook covers it

  • Advanced Nutrition and Human Metabolism, 8th ed. (Gropper) — Glossary

    Ratio comparing the postprandial blood glucose response after consuming 50 g of available carbohydrate from a test food to the response from pure glucose or white bread.

  • duyff-complete-food-and-nutrition-guide-5e

  • Krause and Mahan's Food and the Nutrition Care Process, 16th ed. — Chapter 30

    High-GI foods (>70) raise glucose rapidly; low-GI foods (<55) raise it gradually. GI is affected by food form, processing, fat and protein content, and cooking. Glycemic load (GL) combines GI with portion size and is a more practical measure. Low-GI diets are linked to modest improvements in glycemic control and cardiovascular risk markers in T2DM.

  • Modern Nutrition in Health and Disease, 12th ed. — Ch 3: Carbohydrates

    GI captures carbohydrate quality (kinetics of digestion and absorption) but not quantity. Glycemic load (GL = GI × g carbohydrate / 100) accounts for both. Low-GI diets modestly improve glycemic control and lipids in diabetes but their relative importance versus total carbohydrate, fiber, and dietary pattern is contested. MNHD Ch 3 (Carbohydrates) treats GI as one input among many.

Related terms

Carbohydrate, Carbohydrate Counting, Glycemic Load, Glycemic load, Hyperglycemia, Hypoglycemia, Type 2 Diabetes Mellitus, Type 2 diabetes