Leek Glycemic Index
Low GI · The honest verdict
Gentle on blood sugar
Glycemic index
15–32
reported range
Glycemic load
1
Low GL
This food's glycemic index is 15–32, which is Low GI.
Leeks are a non-starchy vegetable with a low glycemic index and negligible glycemic load, making them a very safe and nutritious choice for people managing blood sugar. Their carbohydrate content is low, and they provide fiber and beneficial plant compounds. 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
Leeks have a low glycemic index (15–32) and a glycemic load of about 1 per half-cup — negligible blood sugar impact.
One half-cup of cooked leeks provides 26.5 mcg of vitamin K — about 22% of the daily value.
Leeks contain kaempferol, a flavonoid antioxidant linked to reduced inflammation and improved heart health.
Harvard T.H. Chan School of Public Health — The Nutrition Source: Flavonoids and Health.
What's actually inside
Per 100 g, with your typical serving noted as 1/2 cup (104 g), cooked, chopped. The carb family is what moves blood sugar — fiber is the number that softens the spike.
- Total carbs
- 7.6g
- Net carbs
- 6.2g
- total carbs minus fiber
- Fiber
- 1.4g
- slows the glucose rise
- Sugars
- 2.1g
- Protein
- 0.8g
- Calories
- 31kcal
Notable nutrients
- Vitamin K26.5 mcg
- Vitamin A (IU)833 IU
- Folate32 mcg
- Manganese0.2 mg
- Iron1.0 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 low-GI choice for blood sugar management
Leeks are a non-starchy vegetable with a low glycemic index and negligible glycemic load, making them a very safe and nutritious choice for people managing blood sugar. Their carbohydrate content is low, and they provide fiber and beneficial plant compounds. This is general nutrition information, not medical advice — people with diabetes should confirm serving guidance with their care team.
Portion guidance
A half-cup serving of cooked leeks (about 104 g) contains roughly 6 g of net carbs and a glycemic load of about 1, which is negligible. Even a full cup (208 g) would have a GL of around 2, still well within the low range. There is no meaningful carbohydrate restriction needed for leeks in normal culinary portions.
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.
Cooking (sautéing, boiling, steaming)
Raises GICooking leeks softens cell walls and gelatinizes their starch, which can modestly raise the GI compared to raw. However, because leeks are naturally very low in total carbs, the increase is minimal and the GI remains low.
Slicing vs. whole cooking
Little effectSlicing leeks increases surface area but does not meaningfully change the GI, as the carb content is low and the fiber structure is not significantly altered by cutting alone.
Adding fats (butter, oil)
Lowers the spikeCooking leeks in butter or olive oil adds fat, which slows gastric emptying and can modestly reduce the overall glycemic response of the meal. This is a favorable pairing for blood sugar stability.
Pairing tip
Leeks pair well with protein sources like chicken, fish, eggs, or legumes, which further stabilize blood sugar. Combining them with other non-starchy vegetables in a stir-fry or soup keeps the meal low in total carbs. Avoid heavy cream or cheese sauces in large quantities if glycemic control is a primary concern, though the leeks themselves are very low impact.
Why GI numbers vary
Published GI data for leeks is limited. The range of 15–32 reflects the few available estimates and reasonable inference from similar low-carb allium vegetables (like onions, which have a GI around 15–30). The variation depends on growing conditions, cooking method, and testing protocols. Because the carb content is so low, even the higher end of the range is firmly low-GI, so the practical takeaway is clear: leeks have minimal glycemic impact.
Not medical advice. This page is general nutrition information about Leek. 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
Leeks have a low glycemic index, estimated between 15 and 32. This range is based on limited direct testing and comparison with similar allium vegetables like onions. Because leeks are very low in total carbohydrates (about 7.6 g per half-cup cooked), even the higher estimate places them firmly in the low-GI category. In practical terms, leeks have a negligible effect on blood sugar.
Yes, leeks are an excellent vegetable choice for people with diabetes. They are low in carbohydrates, have a low glycemic index, and provide fiber, vitamin K, vitamin A, and antioxidants. A half-cup serving has only about 6 g of net carbs and a glycemic load of 1, meaning they will not cause a meaningful blood sugar spike. They can be eaten freely in normal portions as part of a balanced diet. This is general nutrition information, not medical advice.
Leeks and onions are both low-GI allium vegetables with similar nutritional profiles. Onions have a reported GI of about 15–30, very close to leeks. Both are low in carbs per serving and have minimal glycemic impact. Leeks are slightly less carb-dense than onions by weight (7.6 g vs. 10 g per half-cup cooked) and have a milder flavor, but from a blood sugar perspective they are interchangeable as safe, low-impact choices.
Yes, leeks fit well into low-carb and even keto diets in moderate portions. A half-cup of cooked leeks contains about 6 g of net carbs, which is manageable on most low-carb plans (under 50–100 g net carbs/day). On strict keto (under 20–30 g net carbs/day), a half-cup uses a moderate portion of the budget, but leeks can still be included as a flavorful vegetable addition. They are far lower in carbs than starchy vegetables or grains.
Cooking leeks does raise their GI slightly compared to raw, as heat gelatinizes starch and softens fiber. However, because leeks are naturally very low in starch and total carbohydrates, the increase is minimal and the GI remains low. Whether raw in salads or cooked in soups and stir-fries, leeks have a negligible glycemic impact. The cooking method (boiling, steaming, sautéing) makes little practical difference for blood sugar.
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Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed July 2026