Blackberry Glycemic Index
Low GI · The honest verdict
Gentle on blood sugar
Glycemic index
25–40
reported range
Glycemic load
4
Low GL
This food's glycemic index is 25–40, which is Low GI.
Blackberries are one of the most diabetes-friendly fruits thanks to their low GI, very low glycemic load, and high fiber content. A full cup contains only about 6 grams of net carbs, making them suitable for most diabetes meal plans. This is general nutrition information, not medical advice — people with diabetes should confirm serving guidance with their care team.
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
Blackberries have a low GI of 25–40 and a glycemic load of just 4 per cup — among the lowest of all fruits.
One cup of raw blackberries provides nearly 8 g of fiber — about 28% of the daily recommended intake.
Blackberries contain anthocyanins, antioxidants linked to improved insulin sensitivity in some studies.
What's actually inside
Per 100 g, with your typical serving noted as 1 cup (144 g), raw. The carb family is what moves blood sugar — fiber is the number that softens the spike.
Total carbs
13.8g
Net carbs
5.9g
total carbs minus fiber
Fiber
7.9g
slows the glucose rise
- Sugars
- 7g
- Protein
- 2g
- Calories
- 62kcal
Notable nutrients
- Vitamin C30 mg
- Vitamin K29 mcg
- Manganese0.9 mg
- Folate36 mcg
- Copper0.1 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
Excellent choice — low GI, high fiber, minimal sugar impact
Blackberries are one of the most diabetes-friendly fruits thanks to their low GI, very low glycemic load, and high fiber content. A full cup contains only about 6 grams of net carbs, making them suitable for most diabetes meal plans. This is general nutrition information, not medical advice — people with diabetes should confirm serving guidance with their care team.
Portion guidance
A one-cup serving (about 144 g) provides roughly 6 g of net carbs and a glycemic load of 4, which is well within the low GL range. Because blackberries are so low in sugar relative to their volume, most people with diabetes can enjoy 1 to 2 cups per serving without significant blood sugar impact. Pairing with yogurt or nuts adds protein and fat for even steadier glucose response.
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 whole berries
Little effectRaw blackberries retain their full fiber content and intact cell structure, which slows sugar absorption. This is the most blood-sugar-friendly way to eat them.
Blending into smoothies
Raises GIBlending breaks down fiber and cell walls, potentially increasing the glycemic response slightly compared to whole berries. However, the effect is modest because blackberries remain high in soluble fiber even when blended.
Cooking into sauces or jams
Raises GICooking blackberries with added sugar for jams or syrups significantly raises the glycemic impact. The added sugar plus the breakdown of fiber during cooking creates a higher-GI product than fresh berries.
Freezing and thawing
Little effectFreezing blackberries preserves their nutritional profile and fiber content. Thawed berries may release some juice, but the glycemic impact remains essentially the same as fresh.
Pairing tip
Pair blackberries with plain Greek yogurt or cottage cheese for protein that further blunts blood sugar response. A handful of almonds or walnuts adds healthy fat and slows digestion. Avoid sweetening blackberries with sugar or honey — their natural tartness pairs well with a small amount of stevia or cinnamon if needed.
Why GI numbers vary
Blackberry GI data is limited compared to more-studied fruits. The available estimates place blackberries in the 25–40 range, which is consistent with their very low sugar content and high fiber. The variation reflects different testing methodologies and ripeness levels — riper berries have slightly more sugar and a marginally higher GI. We report the honest range (25–40) and classify blackberries as low because all estimates fall well below the low-GI threshold of 55.
Not medical advice. This page is general nutrition information about Blackberry. 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
Blackberries have a low glycemic index estimated at 25 to 40, depending on ripeness and variety. This places them among the lowest-GI fruits available. Their glycemic load for a one-cup serving is only about 4, which is very low. The range reflects real variation across sources, but all estimates confirm blackberries as a low-GI food.
Yes, blackberries are considered one of the best fruit choices for people with diabetes. They are low in sugar (only 7 g per cup), high in fiber (nearly 8 g per cup), and have a very low glycemic load. Their net carb count of about 6 g per cup makes them easy to fit into most meal plans. As always, this is general nutrition information — individuals should discuss their diet with their healthcare team.
Blackberries have a GI similar to strawberries (about 40) and raspberries (about 30–40), and slightly lower than blueberries (about 53). All berries are low-GI fruits, but blackberries and raspberries have the advantage of higher fiber content per cup, which gives them an especially low net carb count. Blueberries are still a good choice but have a bit more sugar.
Yes, blackberries are keto-friendly in moderation. With only about 6 g of net carbs per cup, they fit easily into strict keto (under 20–30 g net carbs/day) and moderate low-carb diets. A half-cup serving provides just 3 g net carbs, making blackberries one of the lowest-carb fruits available. They are a popular choice for keto dieters who want fruit without exceeding their carb limit.
The deep purple-black color of blackberries comes from anthocyanins, which are antioxidant compounds that may have beneficial effects on insulin sensitivity and blood sugar regulation. While the color itself doesn't directly lower GI, the anthocyanin content is associated with metabolic benefits in some research. Riper, darker blackberries may have slightly more sugar but also more antioxidants.
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Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed July 2026