Cool Your Rice Before Eating to Better Manage Blood Sugar

Many people keep rice in "warm mode" after cooking in an electric rice cooker. Those concerned about blood sugar levels should avoid this habit. Cooling freshly cooked rice before eating increases "resistant starch," which benefits blood sugar management.

According to a recent study published in the journal Nutrition & Diabetes, researchers at Sichuan University in China conducted a meta-analysis of 13 diabetes-related studies. The analysis found that resistant starch intake was associated with improvements in fasting blood glucose, insulin resistance, and insulin sensitivity. Glycated hemoglobin and LDL cholesterol levels also decreased.

Resistant starch is a type of starch that resists digestion and acts like dietary fiber. Unlike regular starch, which quickly breaks down into glucose, resistant starch passes through the stomach largely undigested and ferments in the intestines through microbial action. During this process, some is absorbed while the rest is excreted. The extended digestion and transit time prolongs satiety and helps moderate rapid blood sugar spikes.

According to the researchers, cooling carbohydrate foods after cooking rather than eating them immediately increases resistant starch content. For example, rice, potatoes, or pasta can be refrigerated after cooking and then reheated before eating.

Rather than simply increasing overall carbohydrate intake, incorporating foods naturally rich in resistant starch, such as beans, is another effective approach. The research team noted that beans are a representative food high in resistant starch and are not significantly affected by cooking methods.

However, eating only foods containing resistant starch is not advisable, as it may disrupt nutritional balance. Instead, adjusting the proportion of carbohydrates in daily meals and choosing carbohydrate sources relatively higher in resistant starch can be helpful.

A separate study confirmed the effects of "cooled rice" in patients with type 1 diabetes. Researchers at Poznan University of Medical Sciences in Poland had 32 type 1 diabetes patients consume equal amounts of long-grain white rice in either freshly cooked or cooled states, then compared post-meal blood sugar changes. Results showed that eating cooled rice generally lowered peak blood glucose levels and area under the curve (AUC) compared to freshly cooked rice, indicating reduced post-meal blood sugar spikes.

However, caution is warranted. The same study observed that when standard insulin doses were maintained, hypoglycemic episodes occurred more frequently after eating cooled rice. The researchers emphasized that while cooling rice can lower post-meal blood sugar, patients using insulin must coordinate meal planning with insulin adjustment and blood sugar monitoring.