Rice is one of the most widely consumed staples in the world. But if you’re paying attention to your nutrition, you may have heard claims that cooking rice, cooling it overnight, and then eating it the next day reduces its calories. Is this true, or just another diet myth? Let’s break it down.
The Science of Starch in Rice
When rice is cooked, its starch granules undergo a process called gelatinization, which makes the starch easily digestible. This is why freshly cooked rice has a relatively high glycemic impact.
But when rice is cooled—especially overnight—something interesting happens. The starch undergoes retrogradation, reorganizing into a form known as resistant starch.
Resistant starch is not broken down and absorbed in the small intestine like regular starch. Instead, it passes into the large intestine, where it acts more like dietary fiber.
How Many Calories Does Cooling Rice Save?
This process does reduce the number of digestible carbohydrates, but the effect is small. Studies suggest:
- Cooling rice overnight can increase resistant starch by about 1–2% of total starch.
- In calorie terms, a serving of rice (~200 calories) may “lose” only 2–4 calories after cooling.
- Reheating the rice does not completely reverse this effect. Some resistant starch remains, even after warming.
So yes, there is a change, but it is not significant enough to rely on for fat loss.
Benefits Beyond Calories
While the calorie savings are minimal, resistant starch offers several other benefits:
- Better blood sugar control: Resistant starch slows digestion, leading to a steadier release of glucose.
- Improved gut health: It feeds beneficial gut bacteria, producing short-chain fatty acids like butyrate.
- Satiety support: It may help you feel fuller for longer, indirectly supporting weight management.
The Bottom Line
Cooling rice overnight does make some of its starch resistant to digestion, slightly lowering its calorie content. But the reduction is tiny—just a few calories per serving.
The real advantage is not about cutting calories but about supporting digestive health and blood sugar balance. If you enjoy meal prepping or making rice ahead of time, consider this a bonus benefit of letting your rice cool before eating or reheating it.
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