How many carbs are in grapefruit?
Half a medium grapefruit has about 9g of carbohydrate and 8g of net carbs. It is one of the lower-sugar citrus fruits, with less than 8g of sugar per half.
Carbs by portion
| Portion | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| 1/2 grapefruit (123g) | 9.2g | 1.4g | 7.9g |
| 100 grams | 7.5g | 1.1g | 6.4g |
Net carbs
Half a grapefruit has about 8g of net carbs, which is total carbs (9g) minus fiber (1g). The relatively low carb count and high water content make grapefruit one of the more manageable fruits by carb density. See the net carbs guide for when net carbs matter.
Glycemic index of grapefruit
The glycemic index of grapefruit is about 25. Grapefruit has one of the lowest glycemic indexes of any fruit, meaning it raises blood sugar very slowly. The high water and organic acid content both slow digestion.
For diabetes
Half a grapefruit carries about 9g of carbs and has a very low GI of 25, so the blood sugar rise is slow and modest. A full grapefruit (about 18g of carbs) is still workable for most plans. Note that grapefruit contains compounds that interact with several medications including statins, calcium channel blockers, and some blood pressure drugs. If you take any of these, confirm with your pharmacist before eating grapefruit regularly. See the diabetes carb-counting guide.
Keto and low carb
Half a grapefruit has about 8g of net carbs. On a strict 20g keto budget it takes up 40% of your allowance, but it can fit if the rest of the day is very low carb. A whole grapefruit at around 16g of net carbs is harder to fit.
Good to know
Grapefruit juice is a different product from the whole fruit. Eight ounces of pure grapefruit juice has roughly 22g of carbs and almost none of the fiber that slows the rise. The drug interaction concern with grapefruit comes from furanocoumarins in the fruit and juice, not just the pulp, so juice carries the same risk.
Full nutrition (per 100g)
- Calories: 30.0 kcal
- Carbohydrate: 7.5g
- Fiber: 1.1g
- Sugars: n/ag
- Protein: 0.55g
- Fat: 0.1g
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Get the appFrequently asked questions
How many carbs are in grapefruit?
Half a medium grapefruit (123g) has about 9g of carbohydrate. A full grapefruit is roughly 18g of carbs.
How many net carbs are in grapefruit?
Half a grapefruit has about 8g of net carbs, which is total carbs (9g) minus about 1g of fiber.
Is grapefruit low carb?
Yes, relative to most fruit. Half a grapefruit has only 9g of carbs and a GI of 25, making it one of the most diabetes-friendly fruit options.
Is grapefruit keto?
Half a grapefruit is borderline at about 8g of net carbs. It can fit on keto if the rest of the day is very low carb, but a whole grapefruit is harder to accommodate.
Does grapefruit interact with medication?
Yes. Grapefruit contains compounds that block an enzyme that breaks down many common drugs, including some statins and blood pressure medications. Check with your pharmacist if you take any prescription medications.