Fruit · Glycemic index
Do bananas spike blood sugar?
Moderately. Bananas have a low GI of 51, and a 118 g serving (1 medium banana, 7 to 7â inches long) has a medium glycemic load of 12. Bananas have a low average GI, but ripeness shifts it noticeably, and a medium banana carries a medium glycemic load.
Key numbers
- Glycemic index
- 51
- Low GI
- Glycemic load
- 12
- Medium GL
- Available carbs
- 24 g
- 3.1 g fiber
- Serving
- 1 medium banana, 7 to 7â inches long
- 118 g · raw
GI vs GL for bananas
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 â how much carbohydrate a normal serving actually contains: GI Ă available carbs Ă· 100. For bananas: 51 Ă 24 g Ă· 100 â 12.
That figure is an average reported in the 2008 international GI tables (âBanana, raw: 51 ± 3 (average of all available data)â). Ripeness matters: in the 2021 tables, a ripe banana tested 47 and an overripe one 57 in the same Australian laboratory, and cooked green bananas averaged 39.
Eating a different amount? Work out the glycemic load of your portion.
How to eat bananas with less of a spike
- Pick bananas that are yellow with a hint of green rather than heavily spotted; in one laboratory an overripe banana tested 57 against 47 for a ripe one.
- Choose a small banana (about 101 g) or eat half of a large one.
- Pair it with nut butter, yogurt or a handful of nuts.
Lower-GI swaps
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Frequently asked questions
What is the glycemic index of bananas?
Bananas have a glycemic index of 51, which is low. That figure is an average reported in the 2008 international GI tables (âBanana, raw: 51 ± 3 (average of all available data)â). A 118 g serving (1 medium banana, 7 to 7â inches long) contains about 24 g of available carbohydrate, giving a glycemic load of 12 (medium).
Is bananas good for prediabetes?
Bananas can fit into a prediabetes eating plan. Choose a smaller, slightly less ripe banana and eat it with protein or fat â sliced over plain yogurt or with a handful of nuts.
Do riper bananas raise blood sugar more?
Generally, yes. In tests from the same Australian laboratory, a ripe banana had a GI of 47 and an overripe one 57, and cooked green bananas averaged 39 in the 2021 tables. Harvard's Nutrition Source also notes that ripe fruits tend to have a higher GI than unripe ones.
Sources
GI values come from the international GI tables; carbohydrate and fiber per serving are calculated from USDA FoodData Central.
- Atkinson FS, Foster-Powell K, Brand-Miller JC. International tables of glycemic index and glycemic load values: 2008. Diabetes Care. 2008;31(12):2281â2283, Table 1
- USDA FoodData Central, FDC ID 173944: Bananas, raw
- 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):1625â1632, Supplemental Table 1
- Harvard T.H. Chan School of Public Health, The Nutrition Source â Carbohydrates and Blood Sugar
Data last checked .