How to cook rice to lower glycemic index?

October 5, 2025 •

4 min read

Multiple studies show that cooling cooked rice overnight and reheating it can significantly reduce its glycemic impact by creating resistant starch. By mastering how to cook rice to lower glycemic index, you can transform a staple grain into a healthier option for better blood sugar management.

Quick Summary

This guide explores effective cooking techniques to reduce rice's glycemic index, including altering starches through cooling and reheating, incorporating healthy fats, and choosing specific rice varieties. These methods promote better blood sugar control and offer nutritional benefits.

Key Points

Resistant Starch is Key: Cooling cooked rice triggers a process called retrogradation, which creates resistant starch that your body digests slowly, thereby lowering the GI.
Add Healthy Fat to Cook: Mixing a small amount of coconut oil or olive oil into your rice before cooking helps convert digestible starch into resistant starch.
Choose the Right Rice: Varieties like basmati, brown, and parboiled rice are naturally lower on the glycemic index than standard white short-grain rice.
Embrace the Refrigerate-Then-Reheat Cycle: For maximum benefit, refrigerate cooked rice for 12 to 24 hours before eating it. Reheating it later will not destroy the resistant starch that has been formed.
Pair with Purpose: Always combine rice with protein and fiber-rich foods, such as legumes and vegetables, to further slow down digestion and prevent blood sugar spikes.
Avoid Overcooking: Over-boiling rice can increase its GI by breaking down starch molecules more completely. Cook rice until just tender to keep its GI as low as possible.
Consider the 'Drain and Rinse' Method: Boiling rice in extra water and then draining the starchy liquid can also help reduce the GI.

For many, rice is a foundational part of their diet, but its high glycemic index (GI) can be a concern for those managing blood sugar, such as people with diabetes. The GI measures how quickly a food raises blood sugar levels after consumption. Fortunately, several straightforward cooking techniques can alter rice's starch structure, increasing its resistant starch content and lowering its overall GI. This is a game-changer for a balanced nutrition diet.

The Science of Resistant Starch

The secret to lowering rice's GI lies in resistant starch, a type of fiber that your body cannot easily digest. While regular starch is rapidly broken down into glucose, resistant starch passes through the small intestine largely intact. It is then fermented by beneficial gut bacteria in the large intestine, a process that produces short-chain fatty acids like butyrate, which can have positive effects on overall health. The formation of resistant starch is a key strategy for reducing the glycemic impact of starchy foods like rice.

The Cook, Cool, and Reheat Method

One of the most effective and widely researched methods for increasing resistant starch in rice is the simple process of cooking, cooling, and reheating. When rice is cooked, its starch is gelatinized, making it readily digestible. However, as it cools, a process called retrogradation occurs, which converts some of the digestible starch into resistant starch (specifically, RS3).

To apply this method:

Cook the rice normally: Prepare your rice using your preferred method (stove-top or rice cooker).
Cool completely: After cooking, allow the rice to cool to room temperature.
Refrigerate: Place the cooled rice in the refrigerator and chill for at least 12 hours. Research shows that chilling the rice at 4°C for 24 hours can significantly increase its resistant starch content.
Reheat and serve: You can reheat the rice in a microwave or on the stove-top. Reheating does not destroy the resistant starch that has been formed.

Cooking with Healthy Fats

Adding a healthy fat during the cooking process is another scientifically supported method for lowering the GI of rice. The fat molecules form a barrier that interacts with the starch, making it less accessible to digestive enzymes and thus increasing resistant starch (RS5).

The Coconut Oil Technique

Researchers have found that adding a small amount of virgin coconut oil while boiling rice can substantially lower its GI.

Boil water: Bring 1.5 cups of water to a boil for every cup of rice.
Add coconut oil: Add approximately 1 teaspoon of coconut oil per half cup of rice to the boiling water and stir to dissolve.
Add rice and cook: Add the rinsed rice, stir once, then reduce heat, cover, and cook until done.
Refrigerate: For the greatest effect, cool and refrigerate the rice for at least 12 hours before consuming, as this allows the resistant starch to fully form.

Choosing the Right Rice and Pairing It Wisely

Not all rice is created equal. The GI can vary significantly depending on the type of rice due to differences in amylose and amylopectin content. Rice high in amylose (a linear starch) generally has a lower GI than rice high in amylopectin (a branched starch). Choosing the right variety is a crucial first step.

Comparison of Rice Varieties


Rice Type	Amylose Content	Glycemic Index (Typical)	Best Practice for Low GI	Notes
White Short-Grain	Low	High	Use cook, cool, reheat method	Higher GI due to more amylopectin
White Long-Grain	Moderate	Medium to High	Cook al dente, cool, reheat	Better starting point than short-grain
Basmati Rice	High	Low to Medium	Already lower GI; benefit from cooling	Naturally lower GI, fragrant
Brown Rice	High	Medium	Soaking and shorter cooking times	Whole grain, higher fiber content
Parboiled Rice	High	Low	Low GI even when freshly cooked	Processed to move nutrients into endosperm

Other Dietary Considerations

Beyond just the cooking method, you can manage the overall glycemic impact of your meal by considering what you serve with your rice.

Pair with protein and fiber: Combining rice with lean proteins (like chicken or fish), vegetables, and legumes (lentils, chickpeas) slows down digestion and the release of glucose into the bloodstream.
Add an acidic ingredient: A splash of apple cider vinegar in a rice salad can also help reduce the overall GI of the meal by slowing gastric emptying.
Avoid overcooking: Prolonged boiling can increase the GI by breaking down starches more extensively. Cook rice until just done for the best result.
Rinse thoroughly: Rinsing rice before cooking helps remove excess surface starch, which can contribute to a higher GI.

Conclusion

Learning how to cook rice to lower glycemic index is an accessible way to make a healthier food choice without sacrificing your favorite meals. By incorporating methods like adding coconut oil and implementing the cook-cool-reheat cycle, you can increase the resistant starch content and significantly reduce the glycemic impact of rice. Furthermore, choosing rice varieties with a naturally lower GI and pairing them with high-fiber ingredients can contribute to a more balanced diet and better blood sugar control. For those with diabetes or simply seeking to improve metabolic health, these small, consistent changes can lead to meaningful long-term benefits.

For more detailed research on this topic, refer to clinical studies such as those published by the National Institutes of Health.

Key Takeaways

Cook, Cool, and Reheat: Chilling cooked rice for at least 12 hours turns some of its starch into resistant starch, which lowers its GI.
Add Coconut Oil: Incorporating coconut oil during boiling and then cooling increases resistant starch by creating amylose-lipid complexes.
Opt for Low-GI Varieties: Basmati, brown, and parboiled rice have a lower GI than many white rice varieties, making them a better choice.
Control Cooking Time: Avoid overcooking your rice, as this can break down starches and raise the GI.
Combine with Fiber and Protein: Eating rice with legumes, vegetables, and protein helps to slow digestion and balance blood sugar response.
Use Acidic Ingredients: Adding a touch of vinegar, such as in a rice salad, can further lower the glycemic impact of the meal.

Frequently Asked Questions

For optimal resistant starch formation, cool your cooked rice in the refrigerator for a minimum of 12 hours. Some studies suggest that up to 24 hours can yield even better results.

Yes, reheating cooled rice will not destroy the resistant starch that has been created. The modified starch structure is stable and retains its lower glycemic properties even after reheating.

While some studies have focused specifically on coconut oil, other healthy fats like olive oil can also be effective. The key is that the fat interacts with the starches during cooking to promote the formation of resistant starch.

Brown rice generally has a lower GI than most white rice varieties due to its higher fiber content. However, specific types of white rice, such as parboiled and basmati, can have comparable or even lower GI values than brown rice.

Rinsing rice before cooking helps remove excess surface starch. This practice can contribute to a slightly lower GI and better texture, though it is not as impactful as the cooking, cooling, and reheating methods.

Yes, adding acidic ingredients like apple cider vinegar to a rice-based dish can help reduce the overall GI. The acidity slows down gastric emptying and carbohydrate absorption.

While some people perceive minor changes, studies have found no significant difference in the taste or palatability of rice prepared with the cooling and reheating method compared to freshly cooked rice.