Grapefruit Glycemic Index
Low GI · The honest verdict
Gentle on blood sugar
Glycemic index
25
per source
Glycemic load
3
Low GL
This food's glycemic index is 25, which is Low GI.
Grapefruit is one of the lowest-GI fruits and has a very low glycemic load per serving, so it has a gentle effect on blood sugar. Its fiber and water content help slow digestion. However, grapefruit can interact with certain medications, including some statins and blood pressure drugs — people with diabetes should check with their doctor or pharmacist. This is general nutrition information, not medical advice.
GI numbers vary by source, ripeness, and how a food is prepared. This is general nutrition information — not medical advice. If you manage diabetes, confirm specifics with your care team.
Key facts
Grapefruit has a GI of about 25 — one of the lowest among common fruits, comparable to cherries and plums.
Half a medium grapefruit provides 38 mg of vitamin C — about 42% of the daily value.
Grapefruit can interact with over 50 medications, including statins and calcium channel blockers — check with your pharmacist.
What's actually inside
Per 100 g, with your typical serving noted as Half a medium grapefruit (123 g, raw, pink or red). The carb family is what moves blood sugar — fiber is the number that softens the spike.
Total carbs
13.1g
Net carbs
11.4g
total carbs minus fiber
Fiber
1.7g
slows the glucose rise
- Sugars
- 8.1g
- Protein
- 0.9g
- Calories
- 52kcal
Notable nutrients
- Vitamin C38 mg (42% DV)
- Vitamin A1150 IU (23% DV)
- Potassium166 mg
- Lycopene1419 mcg
- Folate15 mcg
Is it a smart choice for blood sugar?
GI is only half the story — portion (glycemic load) and what you eat it with decide the real-world effect. Here's the honest read.
The verdict
Excellent low-GI fruit choice — watch for medication interactions
Grapefruit is one of the lowest-GI fruits and has a very low glycemic load per serving, so it has a gentle effect on blood sugar. Its fiber and water content help slow digestion. However, grapefruit can interact with certain medications, including some statins and blood pressure drugs — people with diabetes should check with their doctor or pharmacist. This is general nutrition information, not medical advice.
Portion guidance
A half grapefruit (about 123 g) provides roughly 11 g net carbs with a glycemic load of 3 — well within the low range. One whole grapefruit doubles the GL to about 6, still low. Grapefruit is one of the few fruits where a full serving is very unlikely to spike blood sugar in most people. Avoid sweetening with sugar or honey, which adds fast-digesting carbs.
This is general nutrition information, not personal medical advice. Blood sugar responses are individual — if you have diabetes or prediabetes, your care team can tell you how this fits your plan.
How to keep the spike small
The same food can land differently depending on how it's cooked and what it's eaten with. Use these levers to your advantage.
Eating whole segments vs. juicing
Lowers the spikeEating the whole fruit with its fibrous membranes preserves fiber that slows sugar absorption. Juicing removes most fiber and concentrates the natural sugars, raising the glycemic effect significantly.
Adding sugar or honey
Raises GIMany people sweeten tart grapefruit with sugar, honey, or agave, which adds fast-digesting simple sugars on top of the fruit's own carbs, substantially raising the glycemic impact of the serving.
Broiling or grilling with cinnamon
Little effectLightly broiling grapefruit halves with a sprinkle of cinnamon caramelizes some natural sugars but does not meaningfully change GI. Cinnamon may have a mild glucose-lowering effect, though evidence is mixed.
Pairing with protein (e.g., cottage cheese)
Lowers the spikeEating grapefruit alongside a protein source like cottage cheese, yogurt, or nuts slows gastric emptying and blunts the blood sugar response further.
Pairing tip
Grapefruit pairs naturally with protein-rich foods: cottage cheese, Greek yogurt, or a handful of almonds. This combination balances the meal and further stabilizes blood sugar. Avoid pairing grapefruit with other high-sugar fruits or sweetened cereals in the same meal. If you take medication, check for grapefruit interactions before making it a regular part of your diet.
Why GI numbers vary
Grapefruit GI values are relatively consistent across sources, typically reported between 22 and 28 for raw fruit. The variation is small and mainly depends on ripeness (riper fruit has slightly more sugar) and variety (white vs. pink/red have similar GI). We report 25 as a well-established consensus value. Grapefruit juice, however, has a higher GI (around 48) due to the loss of fiber.
Not medical advice. This page is general nutrition information about Grapefruit. It isn't a diagnosis or a treatment plan. If you have diabetes, prediabetes, or another condition affecting blood sugar, confirm any dietary decisions with your doctor or care team.
❓Frequently Asked Questions
Grapefruit has a low glycemic index of about 25, making it one of the lowest-GI fruits. This value is well-established across multiple sources, including the University of Sydney GI database. The GI of grapefruit is lower than that of oranges (about 40), apples (about 36), and most other common fruits. The low GI is due to its high water content, moderate fiber, and relatively low sugar density.
Yes, grapefruit is generally considered a good fruit choice for people with diabetes due to its low GI (25) and very low glycemic load (3 per half-fruit). It provides vitamin C, fiber, and antioxidants. However, grapefruit is known to interact with many medications, including certain statins (like atorvastatin and simvastatin), calcium channel blockers, and some blood pressure drugs. Anyone with diabetes should check with their healthcare provider before adding grapefruit to their regular diet. This is general nutrition information, not medical advice.
Grapefruit has a lower GI (25) than oranges (about 40) and a lower glycemic load per serving (3 vs. about 5 for a medium orange). Both are low-GI fruits, but grapefruit is the gentler option for blood sugar. Oranges provide more vitamin C per serving, while grapefruit offers unique compounds like naringin and lycopene (in pink/red varieties). Both fit well in a diabetes-friendly diet.
No, grapefruit juice has a higher GI (about 48) compared to whole grapefruit (about 25). Juicing removes the fiber that slows sugar absorption, concentrating the natural sugars. A cup of grapefruit juice also represents more fruit than you would typically eat whole, increasing the glycemic load. For blood sugar management, whole grapefruit is always the better choice.
Grapefruit has a low GI and GL, meaning it does not raise blood sugar much, but there is no strong evidence that it actively lowers blood sugar in humans. Some animal studies and small human trials have suggested that naringin, a compound in grapefruit, may improve insulin sensitivity, but the evidence is not conclusive enough to make a clinical claim. Grapefruit is a healthy, low-impact fruit choice, but it should not be relied upon as a treatment for diabetes.
Pink and red grapefruit contain more lycopene and beta-carotene than white grapefruit, giving them a higher antioxidant content. However, their glycemic index and nutritional profiles for carbs, fiber, and sugar are very similar. Both are excellent low-GI fruit choices. The color difference does not meaningfully affect blood sugar impact.
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Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed July 2026