The glycemic index (GI) measures how quickly the sugars, or carbohydrates, in food are absorbed. A high glycemic index means that eating the food causes a spike in blood sugar just after consumption, whereas a low glycemic index implies slow, gradual carbohydrate absorption. Studies now show that a healthy diet should be a low-GI diet. Here are the main reasons:
In the short term: it helps stabilize our energy levels
Blood glucose (or sugar) levels must always remain stable. When we raise them excessively by eating high-GI foods, the body reacts by secreting a large amount of insulin, a hormone that moves excess sugar into our cells so they can produce energy, thereby causing blood sugar levels to drop sharply. This leads to "reactive hypoglycemia", the famous post-meal slump: intense fatigue, reduced energy, lack of concentration, stress and anxiety, and... cravings for sweet foods. Sugar calls for more sugar, so beware of the vicious cycle!
In the medium term: it limits weight gain
If this energy generated by carbohydrate intake is not used immediately, the body secretes a hormone, insulin, which stores excess sugar for future needs, first in the liver, then in the muscles (provided there is sufficient muscle mass!), and finally in the form of fat. As you will have understood, consuming too many high-GI foods too regularly promotes weight gain.
In the long term: it reduces the risk of diabetes and cardiovascular disease
Regular and repeated consumption of high-GI foods forces our pancreas to produce large amounts of insulin. Over time, it may become exhausted, leading to the development of conditions such as type 2 diabetes, as well as increased cardiovascular risks and chronic inflammatory diseases.
In practice:
Avoid ultra-processed products containing too much hidden fast-acting sugar, eat whole grains and wholegrain flours, and make sure you always include fiber, high-quality protein, and healthy fats on your plate. All of these slow the rate at which sugar is absorbed and therefore lower the GI of your meal.
Sources: The New GI Diet, Angélique Houlbert and Elvire Nérin
