You have certainly heard of the glycemic index? What does it mean? And what are its impacts on health?

In order to avoid inflammatory and degenerative processes and to slow down the aging process, it is important to consume foods with a low glycemic index (GI).

Since the 1970s, nutritionists have been content to count calories or talk about fast, complex or slow sugars. In the 1980s, researchers realized that these notions did not correspond to any physiological reality. At this point, a key piece of data emerged and the term glycemic index began to be used.

Que signifie l'index glycémique ?

Whether simple or complex sugars, about 30 minutes into their intake always causes a spike in blood sugar (a measure of blood glucose levels). The magnitude of this spike corresponds to the glycemic index (GI) of a carbohydrate-rich food.

This peak or index will vary according to the nature of the carbohydrates contained in a food. Thus, the starch found in cereals, potatoes or legumes will have varying GIs because they contain two types of starch (amylose and amylopectin) in different proportions.

The chemical structure of amylose makes it more resistant to digestive enzymes, while the more rapidly digested amylopectin has a higher GI. One of the consequences proven by experimental studies is that foods rich in amylopectin will make you fatter than those rich in amylose.

Comparaison de différents IG

Cereals (rice, wheat) contain more amylose (25%) than potatoes (20%), and legumes even more (30 to 66%). On the other hand, potatoes contain 80% amylopectin, compared to 75% for cereals (rice, wheat) and 70 to 33% for legumes.

As for fruits, they also contain these 2 types of starches, knowing that these starches tend to convert to simple carbohydrates (sucrose, glucose, and fructose) as the fruit ripens. The GI of a fruit will therefore be lower if it is less ripe.

During cooking, starches gelatinize. This phenomenon is very visible when cooking rice. The gelatinization of this starch makes it much more easily transformed by the digestive juices into glucose. The same phenomenon is observed for well-cooked pasta.

In conclusion, less cooked or "al dente" pasta or rice will have a lower GI.