Grapes: GI, GL, Carbs & Blood Sugar Impact
Glycemic index of grapes (59), glycemic load, carbs per cup, and why portion size matters most for grapes and blood sugar.
Do Grapes Raise Blood Sugar?
Grapes have a moderate published GI (around 59) and a notable sugar load for their weight — a cup carries about 27 g of carbohydrate. The real risk is portion creep: grapes are easy to eat by the handful.
How to Eat It
Measure a portion (about half to one cup) rather than snacking from the bunch. Pairing with cheese or nuts helps. Spring Lee’s fasted test of 148 g of grapes shows what a moderate serving does on a real meter.
Nutrition Facts (Grapes)
| Nutrient | Per 100 g | Per serving |
|---|---|---|
| Calories | 69 kcal | 104 kcal |
| Carbohydrate | 18.1 g | 27.3 g |
| Fiber | 0.9 g | 1.4 g |
| Sugars | 15.5 g | 23.4 g |
| Protein | 0.7 g | 1.1 g |
| Fat | 0.2 g | 0.3 g |
Source: USDA FoodData Central (generic food item, per 100 g edible portion). Values may differ from brand-specific products.
Glycemic Index
Published GI: 59 (typical value).
Reported range: 49-59.
Evidence level: Moderate.
Note: Relatively high sugar content; easy to overeat by the handful.
Sources: International Tables of Glycemic Index and Glycemic Load Values (2008/2021); University of Sydney GI Database (glycemicindex.com). GI values are reported relative to a glucose reference.
Learn more: What is GI? · What is GL? · GI vs GL
Estimated Glycemic Load
GL ≈ 15.3 per 1 cup (151 g).
Calculation: GI (59) × available carbohydrate per serving (26.0 g = 18.1 g − 0.9 g fiber) ÷ 100. Calculated by DMSafeHaven; formula per standard published GL methodology.
- Portion size (grapes are easy to overeat)
- Pairing with cheese or nuts
- Fresh vs. dried (raisins are far more concentrated)
GI values can vary with variety, ripeness, preparation and testing conditions. The value above is a typical published figure, not a universal prediction for every individual or every serving.