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    Oats & breakfast cereals · Glycemic index

    Do steel-cut oats spike blood sugar?

    Moderately. Steel-cut oats have a low GI of 52, and a 240 g serving (1 cup cooked) has a medium glycemic load of 12. Steel-cut oats are the least processed common form of oats, and porridge made from them has the lowest average GI of the three oat styles in the international tables.

    Key numbers

    Glycemic index
    52
    Low GI
    Glycemic load
    12
    Medium GL
    Available carbs
    23 g
    4.1 g fiber
    Serving
    1 cup cooked
    240 g · porridge cooked in water

    GI vs GL for steel-cut oats

    The glycemic index (GI) compares how fast the carbohydrate in a food raises blood sugar against pure glucose (100), using a fixed amount of carbohydrate. The glycemic load (GL) adds the other half of the story — how much carbohydrate a normal serving actually contains: GI × available carbs Ă· 100. For steel-cut oats: 52 × 23 g Ă· 100 ≈ 12.

    That figure is an average reported in the 2021 international GI tables (“Porridge made from steel-cut oats, mean of five foods”). Five steel-cut oat porridges averaged 52. Composition is for oatmeal cooked in water; steel-cut and rolled oats are the same whole grain, so this is a close estimate of the carbohydrate per cup.

    Eating a different amount? Work out the glycemic load of your portion.

    How to eat steel-cut oats with less of a spike

    • Cook a pot at the weekend; steel-cut oats reheat well, which makes a slow-cooking breakfast practical on weekdays.
    • Top the bowl with plain Greek yogurt or a spoon of nut butter for protein and fat.
    • Keep dried fruit to a tablespoon, or use fresh berries instead.

    Lower-GI swaps

    Compare with

    See all 67 foods in the glycemic index table

    Frequently asked questions

    What is the glycemic index of steel-cut oats?

    Steel-cut oats have a glycemic index of 52, which is low. That figure is an average reported in the 2021 international GI tables (“Porridge made from steel-cut oats, mean of five foods”). A 240 g serving (1 cup cooked) contains about 23 g of available carbohydrate, giving a glycemic load of 12 (medium).

    Is steel-cut oats good for prediabetes?

    Steel-cut oats are one of the stronger breakfast choices for prediabetes: low GI, whole grain and a good source of fiber. Watch the add-ons — a small box of raisins adds more carbohydrate than the cup of oats itself.

    Are steel-cut oats worth the extra cooking time?

    For blood sugar, somewhat. Porridge from steel-cut oats averaged a GI of 52 in the 2021 tables, compared with 58 for rolled oats and 82 for instant oats. Batch-cooking and reheating makes the longer cooking time easier to live with.

    Sources

    GI values come from the international GI tables; carbohydrate and fiber per serving are calculated from USDA FoodData Central.

    1. Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr. 2021;114(5):1625–1632, Supplemental Table 1
    2. USDA FoodData Central, FDC ID 2708381: Oatmeal, regular or quick, made with water, no added fat
    3. Harvard T.H. Chan School of Public Health, The Nutrition Source — Carbohydrates and Blood Sugar
    4. USDA FoodData Central, FDC ID 168165: Raisins, dark, seedless (Includes foods for USDA's Food Distribution Program)

    Data last checked .

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