Is it healthier to eat reheated rice?

January 11, 2026 •

4 min read

According to a 2017 study, reheating cooked and cooled parboiled rice can significantly lower the postprandial glycemic response, a key health benefit. But is it healthier to eat reheated rice in all cases, or does it pose a risk? This article explores both the potential benefits and the serious food safety precautions you must take.

Quick Summary

The healthiness of reheated rice is twofold: potential benefits from resistant starch development versus risks from bacterial growth. The critical factor is proper handling and storage to prevent food poisoning. Safe reheating is key to unlocking potential digestive and blood sugar advantages while minimizing risk.

Key Points

Resistant Starch: Properly cooled and reheated rice contains more resistant starch, a fiber-like carbohydrate that benefits gut health and lowers blood sugar impact.
Bacillus Cereus Risk: Cooked rice can contain spores of Bacillus cereus bacteria. If left at room temperature, these spores can multiply and produce heat-resistant toxins that cause food poisoning.
Cooling is Key: The most critical step is cooling cooked rice rapidly, ideally within one hour, by spreading it in a thin layer before refrigerating.
Reheat Thoroughly: To ensure safety, reheated rice must be steaming hot throughout, reaching an internal temperature of at least 165°F (74°C).
Never Reheat Twice: Reheat leftover rice only once. Repeated heating cycles increase the opportunity for dangerous bacteria to multiply.
Storage Time: Refrigerated rice should be consumed within 24 hours for optimal safety.
Trust Your Senses: If rice looks or smells off, or if its storage history is uncertain, throw it away.

The Health Benefits of Reheated Rice

Contrary to popular misconceptions, eating reheated rice can offer specific health benefits when prepared and stored correctly. The primary advantage comes from the creation of resistant starch.

What is Resistant Starch?

Resistant starch is a type of carbohydrate that behaves more like a soluble, fermentable fiber in your digestive system. It bypasses digestion in the stomach and small intestine, instead reaching the large intestine where it feeds beneficial gut bacteria. This process of converting digestible starches into resistant starches is called retrogradation.

When rice is cooked and then cooled, its starch molecules re-crystallize and become more resistant to digestive enzymes. Even when you reheat the rice, a significant portion of this resistant starch remains. Some studies indicate that cooked and then cooled rice can have more than twice the amount of resistant starch than freshly cooked rice.

Impact on Gut Health and Blood Sugar

The increase in resistant starch offers several health advantages:

Improved Gut Health: It acts as a prebiotic, nourishing the good bacteria in your gut. This can lead to a lower gut pH and reduced inflammation.
Lowered Glycemic Response: By decreasing the amount of digestible starch, reheated rice can cause a lower blood sugar spike compared to freshly cooked rice. This can be particularly beneficial for individuals with diabetes or those managing their blood sugar levels.
Enhanced Satiety: Resistant starch can also influence hormones related to appetite control, potentially helping with weight management.

The Critical Food Safety Risk: Bacillus Cereus

While there are health benefits, a significant risk exists if cooked rice is not handled properly. The danger comes from a bacterium called Bacillus cereus, which can cause a type of food poisoning known as "fried rice syndrome".

How Does Contamination Happen?

Bacillus cereus spores are commonly found in dry, uncooked rice and can survive the cooking process. If cooked rice is left to cool slowly at room temperature for an extended period (more than two hours), these surviving spores can germinate into active bacteria. The bacteria then multiply and produce toxins that are heat-resistant, meaning they won't be destroyed by reheating.

Symptoms of Contamination

Symptoms of Bacillus cereus food poisoning can include vomiting (emetic syndrome) or diarrhea and abdominal cramping (diarrheal syndrome), and typically resolve within 24 hours. In rare, severe cases, especially for those with weakened immune systems, more serious complications can occur.

A Comparison of Reheated Rice Scenarios

To clarify the difference between safe and unsafe practices, the following table compares different rice handling methods.


Handling Method	Potential Health Impact	Food Safety Risk	Best Practice Score (1-10)
Freshly Cooked & Served	Standard caloric load. No resistant starch benefits.	Very low, as long as served promptly.	8
Properly Cooled & Reheated	Potential lower glycemic response due to resistant starch.	Very low. Rapid cooling and refrigeration prevent bacterial growth.	9
Left at Room Temp >2hrs, then Reheated	High risk of ingesting heat-resistant bacterial toxins. No health benefit.	High. Reheating will not neutralize toxins from Bacillus cereus.	1
Left at Room Temp >2hrs, Eaten Cold	High risk of ingesting heat-resistant bacterial toxins.	High. Toxins are already present from sitting out.	1

Best Practices for Safe and Healthy Reheated Rice

To reap the benefits of reheated rice while avoiding food poisoning, follow these steps meticulously:

Cooling and Storage

Cool Quickly: As soon as rice is cooked, cool it down rapidly. Spread it out in a thin layer on a clean tray or plate to allow the steam to escape and help it reach room temperature faster.
Refrigerate Promptly: Transfer the rice to the refrigerator within one hour of cooking. Do not leave it out for more than two hours. Store it in a sealed, airtight container.
Use Within 24 Hours: For optimal safety, it's best to eat or use the leftover rice within 24 hours of refrigeration.

Reheating

Ensure It's Steaming Hot: When you reheat the rice, it must be steaming hot all the way through to kill any remaining active bacteria. The target internal temperature is at least 165°F (74°C).
Stir Frequently: Whether you're microwaving or using the stovetop, stir the rice occasionally to ensure even heating and eliminate cold spots. Adding a tablespoon or two of water can help rehydrate it.
Never Reheat More Than Once: Only reheat the portion of rice you plan to eat. Reheating multiple times increases the risk of bacterial growth.

Conclusion

So, is it healthier to eat reheated rice? The answer is nuanced. On one hand, properly stored and reheated rice can be healthier due to an increase in resistant starch, which benefits gut health and moderates blood sugar. On the other hand, improper cooling and storage create a significant risk of food poisoning from Bacillus cereus. The difference between a health-conscious choice and a medical emergency lies entirely in your food handling practices. By following strict and rapid cooling procedures, you can safely enjoy the benefits of reheated rice while minimizing any risk. When in doubt about how long rice has been sitting out, it is always safest to throw it out.

Note: For additional food safety resources, you can consult the official website of the Food Standards Agency.

Frequently Asked Questions

Reheated rice syndrome is a type of food poisoning caused by the bacterium Bacillus cereus. It occurs when cooked rice is left at room temperature for too long, allowing the bacteria to grow and produce heat-resistant toxins. Reheating the rice does not destroy these toxins.

Yes, you can get sick from eating cold leftover rice if it was improperly stored. The issue is not the temperature but the improper cooling process that allowed Bacillus cereus bacteria to multiply and produce toxins. If the rice was cooled and refrigerated quickly, eating it cold is safe.

You should refrigerate cooked rice as quickly as possible, ideally within one hour of cooking. Spreading it into a shallow container can help it cool faster.

Reheating rice can kill active Bacillus cereus bacteria, but it will not destroy the heat-resistant toxins the bacteria may have produced if the rice was left out too long. This is why proper, quick cooling is the most important step.

For some diabetics, reheated rice may be beneficial. The cooling and reheating process increases resistant starch, which can result in a lower and more gradual blood sugar increase compared to freshly cooked rice. However, individuals with diabetes should consult their doctor and carefully monitor their blood glucose levels.

Yes, a food thermometer is an excellent tool to ensure rice is reheated properly. The rice should reach an internal temperature of at least 165°F (74°C) throughout to be safe for consumption.

The risk from Bacillus cereus is not exclusive to white rice; it can affect any cooked starchy food. Both white and brown rice must be handled with the same safety precautions to prevent bacterial growth.