The glycemic index is the ability of a carbohydrate to raise blood glucose (sugar) levels. This indicator measures the amount of glucose in the blood after the decay of the carbohydrate, not the time it takes to decay the carbohydrate. Previously, it was believed that depending on the complexity of the structure of the carbohydrate, its rate of absorption by the body increases. That is, it was believed that a complex carbohydrate would take longer to turn into glucose, and it would take longer for the body to absorb. In fact, this is not the case.
Nowadays, it has been scientifically proven that the complexity of the structure of a carbohydrate does not affect the rate of its conversion into glucose, and hence the rate of absorption by the body. Any carbohydrate, regardless of complexity, will reach its peak blood glucose concentration at the same time. That is, both white bread and buckwheat will reach their peak glucose concentration in about 30 minutes. But the height of this peak (the amount of glucose that will be in your body in 30 minutes) will be different. The glycemic index just shows what this height will be.
What does the glycemic index affect
The glycemic index is a very important criterion for characterizing carbohydrates, because blood glucose directly depends on how much insulin your pancreas produces.
Insulin is a transport hormone that moves carbohydrates through the cells of your body. The more carbohydrates you eat, the more insulin you will have in your body. And the more insulin there is in the body, the more chances you will get extra fat on your body.
What does the glycemic index depend on
The glycemic index depends on the complexity of the carbohydrate structure. Different carbohydrates have different peak blood glucose levels. The simpler the structure of a carbohydrate, the higher a glycemic index it has, the higher it will increase the peak of blood glucose, and therefore, the more insulin will be in the body. Accordingly, the more complex the structure of a carbohydrate, the lower its glycemic index is, the less it will raise the level of glucose in the blood.
The glycemic index of a carbohydrate also depends on the type of heat treatment of a product (boiling, frying, baking, smoking, etc.). During thermal processing of the product, its glycemic index increases. For raw carrot, this index is 35, and for boiled carrot, this index will be as much as 85, which is a lot. The more a carbohydrate is processed, the higher its glycemic index is and the more it increases blood glucose level, and, accordingly, the amount of insulin in the body.
In addition, the glycemic index depends on the presence of fiber in the carbohydrate. The more fiber a carbohydrate contains, the lower its glycemic index is, and the less it raises blood glucose levels. Let’s consider the glycemic index using the example of bread. Take, for comparison, white bread, which is made from white flour, and rye bread, made from wholemeal flour. White bread will have a much higher glycemic index than rye bread, precisely because rye bread will contain more fiber.
The glycemic index in diet planning
When planning a diet (it does not matter for losing weight or for gaining), the glycemic index helps to understand and manage the effectiveness of carbohydrates. You should prioritize complex carbohydrates with low glycemic index that have a lot of fiber. Such carbohydrates do not raise blood sugar levels much, as a result, less insulin is required to carry nutrients through the cells of the body. This means they do not lead to the accumulation of excess fat.
Glycemic index table of basic food
The tables below show carbohydrates with low (up to 40), medium (40-70) and high (over 70) glycemic index. Do not forget that the way of cooking these products can change and increase the glycemic index.
Low, medium and high glycemic carbohydrates
Low glycemic carbohydrates include vegetables, fruits, berries, nuts, some grains, and some legumes.
Carbohydrates with the medium glycemic index include grains, legumes, pasta (from durum wheat), juices and sweet fruits (grapes and others).
High glycemic carbohydrates are the sweetest and most delicious foods: sugar, chips, milk chocolate, sweet buns, etc.