This article is for health education purposes only and is intended for informational reference; it does not constitute medical advice. If you have any health concerns, please consult a professional doctor.

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Freshly cooked rice and rice that has been cooled and then reheated may differ substantially in their impact on blood sugar. A new 2026 study measured rice that was stored after cooking: after cooling, refrigeration, or freezing, resistant starch rose from about 1.8% to nearly 4%, and the glycemic index dropped from 83 to around 44[1].

What do human trials say? In a controlled trial of 32 patients with type 1 diabetes, for the same serving of rice, when it was cooled for 24 hours and then reheated before eating, the 3-hour postprandial blood glucose curve area dropped from 336 to 135, an increase of about 60% less; the peak rise dropped from 3.9 to 2.7 mmol/L[2]. The principle is the same for everyone who eats rice: after cooling, the starch retrogrades and part of it becomes resistant starch that the small intestine cannot absorb, so blood sugar rises more gradually[1][3].

Note that this does not mean you can eat rice freely. Resistant starch does help with insulin sensitivity and weight management[3], but the total amount still counts; controlling blood sugar and losing weight still depend on the overall diet and exercise.

If you want to try it: cook a larger batch of rice at once, portion it out after cooling and refrigerate it, eat it as soon as possible, and reheat it thoroughly before eating. Three reminders: do not leave it at room temperature for long; do not refrigerate it for more than 24 to 48 hours; and if you have diabetes and are taking medication, consult your doctor before changing how you eat.

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Disclaimer: This article is for health education purposes only and is intended for informational reference; it does not constitute medical advice. If you have any health concerns, please consult a professional doctor.

Conflict of interest statement: The content of this article is based on publicly published medical literature, and the author has no relevant conflicts of interest.

References

  1. Impact of post-cooking storage on the glycemic profile of boiled rice: integrating glycemic index, resistant starch, and post-technological stability. Foods. 2026;15(9):1472. PMID:42121416
  2. Influence of resistant starch resulting from the cooling of rice on postprandial glycemia in type 1 diabetes. Nutr Diabetes. 2022;12(1):21. PMID:35429987
  3. Resistant starch intake facilitates weight loss in humans by reshaping the gut microbiota. Nat Metab. 2024;6(3):578-597. PMID:38409604

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