The glycaemic index of a food can show a large degree of natural variability. Now food scientists have observed that something as simple as using chopsticks can change the way a food is eaten and from that, its glycaemic index.
After a meal containing carbohydrate (such as bread, rice, pasta, fruit or even sugar), blood glucose levels initially increase as the food is digested, before returning back to normal levels. The glycaemic index (GI) attempts to characterise these changes in blood sugar levels by measuring blood glucose response over several hours to a test food when compared to a reference food, most commonly pure glucose.
The concept of choosing low GI foods appears to offer some benefit in helping people with diabetes manage their blood sugar levels and also could have a small benefit in weight control.
The difficulty with measuring the GI of a food is that there can be so much variability. The GI of the same food can vary between people, which is why GI is calculated from the average response from many test subjects. How a food is processed, cooked and even the presence of other foods with the meal can all affect the GI.
A novel study has added a further point to consider when looking at GI, and that is how well a food is chewed. Rather than contrive chewing habits, researchers looked at the differences in the GI of rice when it is eaten with chopsticks, a spoon or with fingers. The idea was that different eating methods can mean different rates of eating as too mouthful sizes. All factors that could change the GI.
Using chopsticks to lower the GI
Eleven healthy volunteers attended a food laboratory on 6 non-consecutive days. At each visit they ate a set meal of rice by either chopsticks, spoon or by hand or alternatively ate a reference food of pure glucose (three times) in a random order.
Eating rice by chopsticks gave a significantly lower GI of 68 compared with by spoon where it was 81. Eating by fingers was not considered significantly different to either chopsticks or spoon.
So what could explain this marked difference in GI? Using chopsticks meant a greater number of mouthfuls, chews per mouthful, total chewing time and total time taken to eat the meal. This could also partly explain why the GI of a food can vary between people as we all have different eating speeds even when using the same eating utensils.
What it all means
The idea to chew food well and slowly is well-supported by research in having a benefit in reducing how much food is eaten at a meal. This new study opens up a fascinating avenue of research that slower eating can have flow-on effects to also lower the GI of a meal, and with that further health benefits. Perhaps switching to chopsticks could be one of the most simple lifestyle changes a person could make who is battling with weight and metabolic disease problems.