People who are super health-conscious when it comes to what they eat will probably have come across the term “Glycaemic Index” (GI). It’s what determines the effect of carbohydrates in your food on your blood glucose.
For diabetics, knowing the GI of anything that passes through your mouth is crucial to help you manage your insulin needs. But even if you’re healthy, knowing the GI of your food is important in reducing the risk for conditions such as Type 2 diabetes, heart disease, obesity and colorectal cancer.
According to the HealthHub website, a high GI measures 70 and higher, while a GI of 56 to 69 is considered medium. A low GI can fall between 55 and zero. Foods low in GI can help to prevent and manage diabetes.
But here’s the rub if you’re living in this part of the world – it’s really hard to find any sort of information online if you wanted to find out more about that nasi lemak, char kway teow or mee goreng you just had.
That’s because most of the GI tables are based on western foods and foods consumed in western countries, according to Professor Christiani Jeyakumar Henry, a senior advisor at Agency for Science, Technology and Research’s Singapore Institute of Food and Biotechnology Innovation (SIFBI).
The addition of fat to carbohydrates can lower the GI of foods as fat slows down digestion.
“Given that Asia and this region are epicentres of Type 2 diabetes, it seems a paradox that there were no readily available GI tables to refer to, to select low GI foods,” he told CNA Lifestyle.
‘MOST COMPREHENSIVE’ LIST OF NON-WESTERN FOODS
To rectify that, Prof Henry, along with SIFBI’s senior research officers Rina Quek and Bhupinder Kaur, recently released a list of 940 food items that he said is “the most comprehensive database of GI of non-western foods”.
This data is gleaned from 159 separate studies spanning 2000 to 2020, and the studies don’t only involve diabetics. Out of a conservative estimate of over 2,500 participants, most of the subjects didn't have the condition, according to Prof Henry.
The list of Asian foods, which will be disseminated through Health Promotion Board and Singapore Nutrition Dietetics Association, includes local fare such as lo mai gai (steamed glutinous rice with chicken), mee siam and dosa (crepe made from fermented rice batter).
You’ll also find Malaysia’s lacy pancake eaten with curry, Indonesia’s nasi oyek (a rice-like substitute made of cassava) and the Filipino sponge cake known as mamon.
In fact, the foods featured come from 16 non-western countries, including China, Japan, Thailand, India, Sri Lanka, Saudi Arabia and Lebanon, said Prof Henry.
SURPRISINGLY HIGH-GI LOCAL FOODS RANKED
Love curry puff or lo mai gai? These are two of the high-GI foods in this list of 10 popular foods you may find yourself eating regularly. Here's a look at what the other foods, ranked in descending order, are and why they each have such a high GI:
1. Lo mai gai, GI: 106 - The sticky or glutinous rice is known to have a high GI because of its starchy nature.
2. Chicken curry puff, GI: 92 - Processed flour is often used to make it.
3. Mee siam, GI: 88 - It is made from rice flour, which is high in GI.
4. Chinese yam cake, GI: 86 - Yam has a medium GI but the addition of rice flour causes its overall GI to rise.
5. Rice idli, GI: 85 - It is made from ground rice grains and the more processed the rice grains are, the more rapidly digested the carbohydrates.
6. Chee cheong fun, GI: 81 - See mee siam.
7. Char kway teow, GI: 80 - See mee siam.
8. Rice dosa, GI: 76 - See rice idli.
9. Corn muffin, GI: 74 - Processed flour is often used to make it.
10. Doughnut, GI: 72 - Processed flour and sugar are used.
SO HOW EXACTLY IS A FOOD’S GI DETERMINED?
A food's GI is typically determined by getting the participants to fast overnight. According to HealthHub, they then eat a test food containing 50g of carbohydrate. Their blood samples are then tested at different time intervals for their blood glucose levels.
On a separate day, the same participants are given glucose also containing 50g of carbohydrate and the same blood glucose tests are repeated. The two sets of measurements are then compared, noted HealthHub.
However, a food's GI does not tell you about its nutritional content such as protein, fat, sodium, vitamins and minerals. In fact, a healthier food may have a higher GI than one with lower nutritional value. For example, according to HealthHub, oatmeal has a higher GI than chocolate because of its carbohydrates.
Furthermore, the addition of fat to carbohydrates can lower the GI of foods as fat slows down digestion, noted Prof Henry. Chicken rice has a lower GI than white rice but that doesn't make chicken rice healthier. You'll still need to know a food's nutrition values (there are apps to help with that) or check its nutrition label to decide.
HOW DO YOU GET AROUND HIGH-GI FOODS LIKE WHITE RICE?
Since a food’s GI indicates how quickly its carbohydrates are digested before entering your bloodstream, there are ways to slow down this process. The sequence in which you eat the dishes can play a role, said Prof Henry.
“We need to first eat the vegetables, followed by the meat and then the rice. This sequence slows down the rate of digestion (due to the presence of fibre in the vegetables) and the stimulation of insulin (due to the consumption of meat), thereby facilitating the absorption of glucose into the cells. This, in turn, lowers the GI of rice,” explained Prof Henry.
If you only have one low-GI meal per day, the best is to have it at night.
What you pair with your meal is also crucial. “You must always accompany your rice with a soup (made with meat), soy milk or green tea,” he said, explaining that the protein or amino acids in these liquids have the ability to reduce the rice’s GI.
Having said that, you should try to keep two out of your three meals low GI, advised Prof Henry. “If you only have one option per day, the best is to select a low-GI meal at night, which will have the most impact on your health.”