Simple rice-cooking hack could reduce calories by 60 per cent

Cooking rice with a teaspoon of coconut oil then refrigerating it for 12 hours more than halves the number of calories absorbed by the body, scientists have shown

Cooking rice
Nice rice: master the art of cooking perfectly fluffy rice in three steps Credit: Photo: © Yuji Kotani

It sounds too good to be true but a simple change to the way rice is cooked could reduce its calorie content by 60 per cent.

Scientists in Sri Lanka have discovered that cooking rice with a teaspoon of coconut oil then refrigerating it for 12 hours more than halves the number of calories absorbed by the body. The change remains even if it is reheated.

The researchers from the College of Chemical Sciences in Colombo, Sri Lanka, say simply changing the way rice is cooked could help tackle the obesity epidemic.

"Because obesity is a growing health problem, especially in many developing countries, we wanted to find food-based solutions," says Dr Sudhair James, who is at the College of Chemical Sciences, Colombo, Western, Sri Lanka.

"We discovered that increasing rice resistant starch (RS) concentrations was a novel way to approach the problem."

By using a specific heating and cooking regimen, he says, the scientists concluded that "if the best rice variety is processed, it might reduce the calories by about 50-60 percent."

One in four adults in England is obese and these figures are set to climb to 60 per cent of men, 50 per cent of women, by 2050.

Obesity and diabetes already costs the UK over £5billion every year which is likely to rise to £50 billion in the next 36 years.

Rice contains around 240 calories per cup. The trick to bringing down the calorie content is by changing how the body digests it.

Usually the starchy carbohydrates in rice are broken down in the small intestine where they become glucose and are eventually stored as fat. However, cooking rice with a teaspoon of coconut oil, and then chilling for 12 hours appears to make half of the carbohydrate indigestible so it passes through the body without becoming fat.

"After your body converts carbohydrates into glucose, any leftover fuel gets converted into a polysaccharide carbohydrate called glycogen," added Dr James.

"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."

The team experimented with 38 kinds of rice from Sri Lanka, developing a new way of cooking rice that increased the RS content.

In this method, they added a teaspoon of coconut oil to boiling water. Then, they added a half a cup of rice. They simmered this for 40 minutes, but one could boil it for 20-25 minutes instead, the researchers note.

Then, they refrigerated it for 12 hours. This procedure increased the indigestible starch by 10 times for traditional, non-fortified rice.

It works because the coconut oil enters the starch granules during cooking, essentially changing their architecture so that they are no longer affected by digestive enzymes. SO fewer calories are absorbed into the body.

"The cooling is essential because amylose, the soluble part of the starch, leaves the granules during gelatinization," added Dr James.

"Cooling for 12 hours will lead to formation of hydrogen bonds between the amylose molecules outside the rice grains which also turns it into a resistant starch."

A teaspoon of coconut oil helps change the make-up of rice granules

He says that the next step will be to complete studies with human subjects to learn which varieties of rice might be best suited to the calorie-reduction process.

The team also will check out whether other oils besides coconut have the same effect.

Previous studies have shown that reheating rice can cause food poisoning. However if rice is cooled quickly and not left at room temperature, the NHS says reheating is safe. Rice should also only be kept for a day and reheated rice should be checked to make sure it is steaming hot all the way through. Never reheat more than once.

The research was presented at the national Meeting & Exposition of the American Chemical Society