How to make rice digest slower: A guide to lowering glycemic index

November 8, 2025 •

3 min read

Research from the College of Chemical Sciences in Sri Lanka found that adding coconut oil and cooling rice can reduce its digestible calories significantly. This and other simple cooking hacks can help you understand how to make rice digest slower for better blood sugar management and prolonged satiety.

Quick Summary

Changing cooking methods can increase rice's resistant starch content, which slows digestion. Techniques include cooling cooked rice, adding healthy fats, choosing whole-grain varieties, and pairing it with protein and fiber. These adjustments help manage blood sugar levels and promote better gut health.

Key Points

Cook and Cool: Cook rice and then refrigerate it for at least 12 hours to increase resistant starch, lowering its glycemic index.
Add Healthy Fats: Incorporate a teaspoon of coconut oil per half-cup of rice during cooking to form a protective layer that slows digestion.
Choose Whole Grains: Opt for brown rice or parboiled rice, which contain more fiber or have altered starch structures that promote slower digestion.
Pair with Protein and Fiber: Serving rice with legumes, vegetables, and lean protein significantly slows the overall digestion of the meal.
Use Vinegar: Adding apple cider vinegar to a cold rice salad can help slow gastric emptying and carbohydrate absorption.
Reheat Safely: Reheating cooled rice does not destroy the resistant starch benefits, allowing you to enjoy the meal warm.

The Science Behind Slowing Rice Digestion

When we eat rice, our bodies break down its starches into simple sugars, causing a rapid spike in blood sugar. For many people, especially those managing diabetes or aiming for stable energy levels, a slow and steady release of glucose is more desirable. The key to achieving this lies in altering the starches within the rice to create what is known as 'resistant starch'. Resistant starch is a type of carbohydrate that resists digestion in the small intestine and instead ferments in the large intestine, feeding beneficial gut bacteria and leading to a more gradual glucose release. Several simple, yet effective, kitchen techniques can maximize the formation of this resistant starch.

Cooking and Cooling for Resistant Starch

One of the most effective methods to increase resistant starch in rice is cooking and then cooling it, a process called retrogradation. As rice cools, starch molecules realign into a structure that's harder for digestive enzymes to break down, slowing glucose release. Cooking rice and refrigerating it for at least 12 hours can significantly increase resistant starch. The resistant starch benefits remain even after reheating.

Adding Fats to Slow Digestion

Incorporating healthy fats during cooking can also slow starch breakdown. Adding a teaspoon of coconut oil per half-cup of rice while cooking, followed by chilling, may reduce calorie absorption by over 50%. Other healthy fats like ghee or olive oil can also be used.

Opt for Lower-GI Rice Varieties

Some rice types have a lower glycemic index (GI), causing a less dramatic blood sugar spike:

Brown Rice: As a whole grain, its fiber-rich bran and germ slow digestion.
Basmati Rice: This long-grain rice typically has a lower GI than shorter grains.
Parboiled Rice: The parboiling process changes the starch structure, lowering its GI.

Pair Rice with Fiber and Protein

Combining rice with other foods is a simple way to slow digestion. Fiber and protein act as natural digestive brakes.

Legumes: Lentils, beans, or chickpeas add fiber and protein, delaying gastric emptying.
Vegetables: Fibrous vegetables moderate the meal's overall GI.
Lean Protein: Serving rice with lean protein balances the meal and slows digestion.

Cooking Methods for Lowering Rice's GI: A Comparison


Method	Primary Mechanism	Best For	Considerations
Cook & Cool	Increases resistant starch (retrogradation)	Meal prep, salads, reheating leftovers	Requires planning ahead (at least 12 hours cooling)
Add Coconut Oil	Fat forms barrier, creates resistant starch	White rice, low-calorie variations	May alter flavor slightly; best combined with cooling
Choose Brown Rice	Higher fiber content slows digestion	All meals, especially if high-fiber diet is desired	Requires longer cooking time than white rice
Pair with Protein/Fiber	Slows gastric emptying, balances meal	Instant GI reduction for any rice type	Focuses on overall meal composition, not just rice
Use Parboiled Rice	Altered starch structure lowers GI	Quick preparation, similar to white rice	Pre-treated, so less cooking-based GI control

A Step-by-Step Guide to Cooking Slower-Digesting Rice

Follow these steps to increase resistant starch in white rice:

Rinse the rice: Wash thoroughly to remove excess surface starch.
Add coconut oil: Bring water to a boil (2 cups water per 1 cup rice). Add 1 teaspoon of coconut oil.
Cook normally: Add rice, reduce heat, cover, and simmer for 15-20 minutes.
Cool completely: Transfer to a shallow dish and refrigerate for at least 12 hours.
Reheat and serve: Reheat safely; resistant starch benefits remain.

Conclusion

Making rice digest slower helps manage blood sugar and promotes better digestive health. Using methods like cooking and cooling to create resistant starch, adding healthy fats such as coconut oil, choosing whole-grain varieties, and pairing rice with fiber and protein can transform rice into a more balanced energy source. These simple cooking adjustments can have a significant positive impact on your health. For additional scientific details, refer to academic resources like the Asia Pacific Journal of Clinical Nutrition: https://pubmed.ncbi.nlm.nih.gov/26693746/.

Frequently Asked Questions

Cooling cooked rice causes its starch molecules to rearrange into a more compact structure called resistant starch. This type of starch is harder for the body to digest, leading to a slower release of glucose into the bloodstream.

Yes, reheating cooled rice will not destroy the resistant starch. The molecular structure of the reformed starch is heat-resistant, so you can safely enjoy the reheated rice with its slower-digesting properties intact.

The cooking and cooling method works for all starchy foods, including different varieties of rice like white and brown rice. Some rices, like brown rice and basmati, have a naturally lower GI to begin with.

When cooked with rice, coconut oil enters the starch granules and creates a barrier. This barrier makes it more difficult for digestive enzymes to access and break down the starch, slowing the absorption of glucose.

Brown rice is a whole grain that contains more fiber than white rice. This higher fiber content requires more time and effort for your digestive system to break down, resulting in slower digestion and a more gradual increase in blood sugar.

Both protein and fiber slow down the process of gastric emptying, which is how quickly food leaves the stomach. This means the overall absorption of nutrients, including carbohydrates from rice, is slower and more sustained.

No, you do not have to eat the rice cold. While the cooling process is essential for creating resistant starch, you can reheat the rice and still receive the benefits of its lower glycemic index.