Glycemic Index (GI) and its impact on our health 

Blood sugar spikes from high glycemic index (GI) foods can lead to serious health risks in the long term, especially for those with impaired glucose tolerance (i.e., diabetics) and those at risk for diabetes. More people are turning to use GI as a way to help plan out their meals. So, what exactly is GI and how can consuming lower GI foods improve our health? Read on to find out what GI is and its impact on our health.

What is Glycemic Index (GI)? 

The glycemic index (GI) is a relative scale from one to 100 that ranks the impact of carbohydrates on blood glucose levels after consumption.  

How is a GI (Glycemic Index) guide useful? 

A GI guide on commonly consumed foods in the daily diet is a great resource to help better manage blood sugar levels. If we are mindful of foods containing high GI, we can make a conscious effort to consume lesser portions or in moderation.  

Consuming lower or moderate GI foods helps to prevent unwanted spikes in glucose levels post-meals. Preventing blood glucose spikes is important for: 

• Effective diabetes management 
• Generally, lower the risk of diabetes, particularly in high-risk individuals (Take a Diabetes Risk Assessment by Health Hub) 
• General health maintenance with a balanced diet, and to maintain or manage weight gain or loss 

How GI (Glycemic Index) of foods are categorised:  

GI levels of commonly consumed foods can be categorised into three ranges:  

Low GI (less than 55) – Beans, porridge, oats, broccoli, mushrooms, lentils, etc. 

Medium GI (55 to 70) – Mango, banana, cous cous, corn, brown rice (read more about the Types of Rice and its GI), boiled sweet potatoes, etc. 

High GI (more than 70) – White bread, white rice, taco shells, spaghetti, chocolates, popcorn, etc. 

Carbohydrates with lower GI are absorbed and digested by the body at a slower rate. This helps to control glucose levels by slowing down glucose release and manages weight by keeping you full for a longer period. Also, consuming lower GI foods can help to reduce cholesterol levels in time and help to prevent heart diseases.  

On the other hand, consuming high GI carbohydrates can cause a spike in blood glucose levels. With sustained increase in blood glucose levels, there is a higher risk for developing Type 2 Diabetes, heart diseases, obesity and other health related problems. 

What affects the GI level of food? 

Physical attributes of food 

The size, texture and ripeness of carbohydrate foods affect the GI level. For example, the GI of a ripe banana is 51, while the GI of an unripe banana is 30.  

Food pairing 

Depending on whether the food is consumed with other foods or on its own, the impact on your blood glucose will differ accordingly. Consuming refined carbohydrates with proteins and fats lowers the GI of these carbohydrates. 

Portion sizes 

The amount of carbohydrate foods being consumed holds as much importance as the GI of the food.  

For instance, a slice of watermelon has a low glycemic load even though it is generally a fruit that has high GI. Though white rice has a comparable GI, its glycemic load is higher as it contains more carbohydrates than a slice of watermelon. 

Read more about glycemic load.

Cooking method 

The cooking methods and processing of a food affects the GI as well. Food that has been cooked for a longer period tends to be higher GI as the food is broken down into finer pieces and they are more easily absorbed. Some food also contains lower GI when eaten cold instead of when they are hot. 

Presence of fat and/or acid 

When fat or acid is added to a carbohydrate food, its conversion into glucose slows down and becomes absorbed more slowly into the bloodstream. Acidic food such as vinegar and lemon, or fermenting food, will help to lower the GI of a meal as it helps to delay emptying of the stomach. 

Presence of fibre 

Rapid attacks by digestive enzymes to starchy carbohydrates are protected by fibre, which also helps to slow down the digestion in the digestive tracts. This results in slowing down the process of converting carbohydrates to glucose. 

Should I also take note on the GI levels of food even though I am healthy and well? 

Yes, of course. It is always important to maintain good health and body conditions by taking note of what you are consuming and putting into your body. As the saying goes, you are what you eat. Our daily choice of foods and diets play a vital role in determining our health in the long run.  

Thus, opt for healthier options whenever you can and consume food in moderation even on cheat days. 

You can check the glycemic index (GI) and glycemic load of foods to help you with planning out your meals.