Fruit · Glycemic index
Do grapes spike blood sugar?
Moderately. Grapes have a low GI of 54, and a 151 g serving (1 cup) has a medium glycemic load of 14. Grapes have a low GI, but they are easy to eat by the handful and a cup carries a medium glycemic load.
Key numbers
- Glycemic index
- 54
- Low GI
- Glycemic load
- 14
- Medium GL
- Available carbs
- 26 g
- 1.4 g fiber
- Serving
- 1 cup
- 151 g · raw
GI vs GL for grapes
The glycemic index (GI) compares how fast the carbohydrate in a food raises blood sugar against pure glucose (100), using a fixed amount of carbohydrate. The glycemic load (GL) adds the other half of the story — how much carbohydrate a normal serving actually contains: GI × available carbs ÷ 100. For grapes: 54 × 26 g ÷ 100 ≈ 14.
That figure comes from a single published test in the 2021 international GI tables (“Grapes, green, Menidee, seedless (Australia, 2008)”), so treat it as approximate. No published mean exists. Two ISO-standard tests in the 2021 tables found 50 (red Crimson seedless) and 54 (green seedless); the higher value is shown. An older test of black grapes found 59.
Eating a different amount? Work out the glycemic load of your portion.
How to eat grapes with less of a spike
- Portion out half a cup — roughly 15 grapes — instead of snacking from the bunch.
- Pair them with a little cheese or a few almonds.
- Choose whole grapes over raisins; drying packs the same sugar into a much smaller handful.
Lower-GI swaps
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Frequently asked questions
What is the glycemic index of grapes?
Grapes have a glycemic index of 54, which is low. That figure comes from a single published test in the 2021 international GI tables (“Grapes, green, Menidee, seedless (Australia, 2008)”), so treat it as approximate. A 151 g serving (1 cup) contains about 26 g of available carbohydrate, giving a glycemic load of 14 (medium).
Is grapes good for prediabetes?
Grapes are fine for prediabetes when portioned: count out a small bowl rather than eating from the bunch, and have them with cheese or nuts.
Are red or green grapes better for blood sugar?
There is little difference. In the 2021 international tables, red Crimson seedless grapes tested 50 and green seedless grapes 54 — both in the low band.
Sources
GI values come from the international GI tables; carbohydrate and fiber per serving are calculated from USDA FoodData Central.
- Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr. 2021;114(5):1625–1632, Supplemental Table 1
- USDA FoodData Central, FDC ID 174683: Grapes, red or green (European type, such as Thompson seedless), raw
- Atkinson FS, Foster-Powell K, Brand-Miller JC. International tables of glycemic index and glycemic load values: 2008 — online appendix, Table A1
- USDA FoodData Central, FDC ID 168165: Raisins, dark, seedless (Includes foods for USDA's Food Distribution Program)
Data last checked .