In a molecular gastronomy-meets-lab-science moment, researchers at the College of Chemical Sciences in Colombo, Sri Lanka, have discovered a method of cooking rice that appears to cut the calories the body absorbs from the rice by more than half. The study results—reported at the end of March at the 249th National Meeting & Exposition of the American Chemical Society— showed that rice, when cooked using this protocol, could be a good low-calorie food source for reducing obesity, said the scientists.
The team experimented with 38 kinds of rice from Sri Lanka, arriving at a new way of cooking that increases the grain’s resistant starch (RS), or nondigestible starch, content. The simple recipe calls for adding 1 teaspoon of pure coconut oil to boiling water and then adding half a cup of rice. The mixture simmers for 40 minutes (or it could be boiled for 20–25 minutes) and is then refrigerated for 12 hours. In the study, the procedure increased RS 10-fold for traditional, nonfortified rice.
“Because obesity is a growing health problem, especially in many developing countries, we wanted to find food-based solutions,” said team leader Sudhair A. James. “We discovered that increasing RS concentrations was a novel way to approach the problem.”
By using a specific heating and cooking regimen, he said, the scientists concluded that “if the best rice variety is processed [this way], it might reduce the calories by about 50%–60%.”
James explains that starch can be digestible or indigestible. Starch is a component of rice, and it has both types. Unlike digestible types of starch, RS is not broken down in the small intestine, where carbohydrates are normally metabolized into glucose and other simple sugars and absorbed into the bloodstream. Thus, the researchers reasoned that if they could transform digestible starch into RS, then they could lower the number of usable calories in the rice.
Rice is loaded with starch (1.6 ounces in a cup), says James. “After your body converts carbohydrates into glucose, any leftover fuel gets converted into a polysaccharide carbohydrate called glycogen,” he explained. “Your liver and muscles store glycogen for energy and quickly turn it back into glucose as needed. The issue is that the excess glucose that doesn’t get converted to glycogen ends up turning into fat, which can lead to excessive weight or obesity.”