Glycemic index (Glycaemic index)

Introduction

Tables of Glycemic Indexes

Interesting facts

Introduction

  Glycemic Index (Glycaemic Index) (GI) is a list of products ranked in view of glucose level in blood after their consumption. It is calculated by dividing glucose level in blood after conducting a nourishing test with share of 50 g of carbohydrates by the glucose level received after a particular product consumption. For instance glycemic index which is equal 70 means that after consumption of 50 g of a particular product the glucose level will increase of 70%, as after consumption of 50 g of pure glucose. Glycemic index of food cannot be established on the base of its composition or indexes of carbohydrates contained in this food. To set it one should give a particular product to a particular person. The particular product is given to a group of people every second hour, every quarter an hour their blood is collected and the sugar level is checked. In that way the average value of GI is obtained. It has been claimed the mean value is repeatable and tests conducted in different groups of volunteers give close results. Results received in people suffering from diabetes are comparable with results of healthy people. The higher GI value of a particular product the higher glucose level in blood after its consumption. Having eaten carbohydrate of high GI leads to a rapid increase of sugar level causing high insulin burst in response. The level of sugar quickly drops down and similarly to a pendulum which has tilt to one side and has to do the same to the opposite one - the sugar level does not decrease to the output value but significantly lower, badly tolerated by organism and called hypoglycemia. Apart from different unpleasant feelings a symptom of hypoglycemia is hunger. The willingness to satisfy it is a reason of uncontrolled eating. Products of high GI are conducive to weight gaining in two ways: they provoke hunger what is conducive to more frequent eating and they act anabolically thanks causing high increases of insulin level. Insulin regulates sugar level but also results in activation of processes of absorption and storing defined by the name of anabolism, what practically means weight gaining. Insulin activates processes of neolipogenesis - fat forming - mainly from provided carbohydrates. In such form storing follows. Additionally insulin makes easier depositing of fats circulating in blood serum to fatty cells. So it is so-called anabolical hormone.
   High insulin level is conducive to weight gaining. Such high level is associated with some groups of carbohydrates, which in rapid and significant way increase momentary glucose level in blood serum, in other words they have so-called high glycemic index (higher or equal 70), whereas consumption of product of low glycemic index causes slow and relatively small increase of sugar level and what fallows - little insulin burst. Such products are not allies of weight gaining. It is worth to remember that processing of foodstuffs (heat treatment, heat treatment time) increases their glycemic index.

Tables of Glycemic Indexes

Glycemic Index (Glycaemic Index) range

Low GI = 55 or less
Medium GI = 56-69
High GI = 70 or more

Interesting facts

  Glycemic index (Glycaemic index) of foodstuffs consumed in their natural form is much lower than of ones cooked or processed in any other way. Whole-wheat cereals and bakery products made from whole-wheat flour contain much fiber, vitamins and marginal elements, which have the ability to lower high glucose level in blood. To make glycemic index of eaten goods not high we must take into consideration the following aspects:

• dietary fiber (dietary fibre) delays carbohydrate transformation by partial denying of glucose to blood access. It can also increase the sensitivity of receptors susceptible to insulin in a muscle in the way that glucose easier reaches to a cell. If receptors are low-sensitive, then pancreas increases insulin secretion to balance glucose inflow to cells of muscles,

• the form of product - if it is grained or processed in any other way, if whole-wheat grains or fibers occur in it,

• the level of preparation or cooking what allows to check starch content,

• fructose or lactose presence (both have low glycemic index),

• the time of food consumption, it affects glucose secretion to blood - the faster you it the faster it is,

• products rich in fats, of low glycemic index may be wrong classified, because fats and protein slow down stomach emptying, and what is the same the speed of digestion in small intestine, so their glycemic index may be relevantly lower than the one of products containing less fat.