Watermelon: GI, GL, Carbs & Blood Sugar Impact

Q: "What is the GI of Watermelon?"

"The typical published GI of Watermelon is 76, with a reported range of 72-80 (evidence level: Moderate)."

Q: "How many carbohydrates are in Watermelon?"

"About 21.3 g per 2 cups diced (280 g) (7.6 g per 100 g), including 1.1 g of fiber."

Q: "Is Watermelon suitable for people with diabetes?"

"A classic example of GI not being the whole story: high GI, but GL is moderate because a serving is mostly water."

Q: "What is the estimated glycemic load of Watermelon?"

"About 15.3 per 2 cups diced (280 g), calculated as GI × available carbohydrate ÷ 100. See the methodology for the exact formula."

Glycemic index of watermelon (76), glycemic load, carbs per serving, and why high GI watermelon can still fit a diabetes diet.

Category: Fruits · Nutrition data source: USDA FoodData Central · GI source: International Tables of GI & GL Values / University of Sydney · Last verified:

76 Glycemic Index High

15.3 Estimated GL 2 cups diced (280 g)

21.3 g Carbohydrate per 2 cups diced (280 g)

1.1 g Fiber per 2 cups diced (280 g)

Does Watermelon Raise Blood Sugar?

Watermelon has a high published GI (around 76), which surprises people — but a serving is mostly water. Two cups carry about 21 g of carbohydrate, giving a moderate GL. GI alone overstates its impact; the portion is what decides.

How to Eat It

Keep the portion around a cup or two, and treat it as part of the day’s carbohydrate budget. Eating it after a protein-containing meal further flattens the response.

Nutrition Facts (Watermelon)

Nutrient	Per 100 g	Per serving
Calories	30 kcal	84 kcal
Carbohydrate	7.6 g	21.3 g
Fiber	0.4 g	1.1 g
Sugars	6.2 g	17.4 g
Protein	0.6 g	1.7 g
Fat	0.2 g	0.6 g

Source: USDA FoodData Central, record FDC ID 167765 ("Watermelon, raw"). Values may differ from brand-specific products.

Glycemic Index

Published GI: 76 (typical value).
Reported range: 72-80.
Evidence level: Moderate.
Note: High GI but mostly water - the per-serving carbohydrate load stays moderate at a normal portion.

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 2 cups diced (280 g).

Calculation: GI (76) × available carbohydrate per serving (20.2 g = 7.6 g − 0.4 g fiber) ÷ 100. Calculated by DMSafeHaven; formula per standard published GL methodology.

Diabetes consideration: A classic example of GI not being the whole story: high GI, but GL is moderate because a serving is mostly water.

What can change the impact?

Portion size
How ripe the melon is
Eating it alone vs. after a protein-containing meal

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.

Frequently Asked Questions

What is the GI of Watermelon?

The typical published GI of Watermelon is 76, with a reported range of 72-80 (evidence level: Moderate).

How many carbohydrates are in Watermelon?

About 21.3 g per 2 cups diced (280 g) (7.6 g per 100 g), including 1.1 g of fiber.

Is Watermelon suitable for people with diabetes?

A classic example of GI not being the whole story: high GI, but GL is moderate because a serving is mostly water.

What is the estimated glycemic load of Watermelon?

About 15.3 per 2 cups diced (280 g), calculated as GI × available carbohydrate ÷ 100. See the methodology for the exact formula.

DMSafeHaven provides educational information based on publicly available nutrition databases and published research. It is not a substitute for individualized medical advice. Nutrition values: USDA FoodData Central (CC0). GI values: published tables (see methodology). GI/GL estimates do not predict any individual's glucose response — test your own blood glucose with your care team's guidance.