Starfruit Glycemic Index
Low GI · The honest verdict
Gentle on blood sugar
Glycemic index
30–42
reported range
Glycemic load
3
Low GL
This food's glycemic index is 30–42, which is Low GI.
Starfruit is a very low-calorie, low-carb, low-GI fruit that has minimal impact on blood sugar. However, it contains oxalic acid and caramboxin — compounds that are harmless to healthy kidneys but can be toxic for people with kidney disease or on dialysis. This is general nutrition information, not medical advice; people with diabetes or kidney conditions should discuss starfruit with their care team before eating it.
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
One medium starfruit is about 92% water and contains only 28 calories, making it one of the lowest-calorie fruit choices.
Starfruit (carambola) contains caramboxin, a neurotoxin that healthy kidneys excrete but that can accumulate dangerously in people with kidney disease.
A glycemic load of 10 or under is classified as low; starfruit scores approximately 3 per medium fruit.
What's actually inside
Per 100 g, with your typical serving noted as 1 medium starfruit (91 g), raw. The carb family is what moves blood sugar — fiber is the number that softens the spike.
- Total carbs
- 6.7g
- Net carbs
- 5.3g
- total carbs minus fiber
- Fiber
- 2.8g
- slows the glucose rise
- Sugars
- 3.9g
- Protein
- 0.9g
- Calories
- 28kcal
Notable nutrients
- Vitamin C34 mg
- Copper0.13 mg
- Potassium121 mg
- Vitamin B5 (pantothenic acid)0.39 mg
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
Blood-sugar-friendly in normal portions — but avoid if you have kidney disease
Starfruit is a very low-calorie, low-carb, low-GI fruit that has minimal impact on blood sugar. However, it contains oxalic acid and caramboxin — compounds that are harmless to healthy kidneys but can be toxic for people with kidney disease or on dialysis. This is general nutrition information, not medical advice; people with diabetes or kidney conditions should discuss starfruit with their care team before eating it.
Portion guidance
One medium starfruit (about 90 g) provides only about 5 g of net carbs and a GL of roughly 3 — very low. Even two fruits remain well within low-GL territory. For people with healthy kidneys and blood-sugar management goals, starfruit is an easy addition; for those with any kidney impairment, it should be avoided regardless of glycemic concerns.
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 raw and whole
Lowers the spikeRaw starfruit retains its full fiber content and structure, which slows sugar absorption and maintains the naturally low glycemic response.
Juicing
Raises GIStarfruit juice removes fiber and concentrates sugar. It also concentrates the oxalic acid and caramboxin that make starfruit dangerous for people with kidney disease — an additional safety reason to prefer the whole fruit.
Riper fruit
Raises GIStarfruit sweetens as it ripens and turns from green to golden-yellow. Very ripe fruit has more sugar and a somewhat higher glycemic response than firm, barely-ripe fruit.
Pairing with protein or fat
Lowers the spikeLike any low-carb fruit, pairing with a protein or fat source (cheese, yogurt, nuts) slows gastric emptying and flattens the already-small glucose curve.
Pairing tip
Starfruit is naturally low-carb and visually striking — sliced crosswise, each piece forms a star shape. Add raw slices to salads with leafy greens and olive oil, or serve alongside grilled fish or shrimp. The tartness contrasts well with creamy elements like avocado or feta. Avoid candied preparations, which add substantial sugar.
Why GI numbers vary
Formal GI studies on starfruit are extremely limited. The estimated 30–42 range is based on its macronutrient profile — high water content (~92%), low sugar (~4 g per fruit), and moderate fiber (~2.8 g) — and extrapolation from comparable low-carb tropical fruits. We report a range rather than a fabricated precise number because direct GI testing data for starfruit is essentially unpublished.
Not medical advice. This page is general nutrition information about Starfruit. 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
Starfruit is estimated to have a low GI — roughly 30 to 42 — based on its very low carbohydrate content, high water content, and fiber. Formal GI testing studies on starfruit are extremely limited, so this is an honest range estimate rather than a precisely studied value. One medium fruit has only about 5 g of net carbs, making glycemic load (around 3) more informative than GI alone.
For people with diabetes who have healthy kidneys, starfruit is generally a blood-sugar-friendly choice — very low in carbs and calories with a gentle glucose response. However, starfruit contains caramboxin and oxalic acid that are toxic for people with kidney disease. Since diabetes can cause kidney damage over time, anyone with any kidney impairment should avoid starfruit and discuss this with their nephrologist or diabetes care team.
Starfruit contains a neurotoxin called caramboxin and high levels of oxalic acid. Healthy kidneys filter these out safely, but impaired kidneys cannot. For people with chronic kidney disease or on dialysis, eating starfruit — even a small amount — can cause hiccups, vomiting, seizures, and in severe cases, death. This is a well-documented clinical contraindication, not a minor caution.
Only minimally. One medium starfruit contains about 6.7 g of total carbs and 3.9 g of natural sugars — very low for a piece of fruit. Combined with its fiber content and high water content (~92%), the blood sugar impact is very modest. It is one of the lowest-carb tropical fruits available.
Starfruit compares favorably to most tropical fruits — it is significantly lower in carbs and glycemic load than mango, pineapple, or papaya. It is more comparable to guava in glycemic impact. Among tropical fruits, starfruit and guava are generally considered the best options for blood sugar management, assuming no kidney concerns.
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Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed July 2026