If many people are familiar with the energy value measured in calories, then such a thing as a “glycemic index” is known only to a few. What does it mean? Who and why should know him?
To understand the essence of the concept, it is necessary to understand the purpose of carbohydrates. They are used by the body to produce the energy necessary for the work of all important organs and systems. But carbohydrates can be different. So, simple almost immediately absorbed through the walls of the digestive tract into the bloodstream and provoke an increase in the level of glucose in it.
As a result, often the body simply does not have time to recycle energy, and it goes "in reserve", that is, the formation of fatty deposits. But complex carbohydrates are absorbed gradually, which allows the body to receive energy in portions and use it properly.
So what is the glycemic index of foods? This is an indicator that determines the rate of splitting of carbohydrates and the degree of increase in the level of glucose in the blood. If it is high, then there is a sharp increase in the amount of glucose. If the index is low, then its level changes slowly or remains almost unchanged.
Such a concept was discovered in 1981 by David Jenkins, who was engaged in the development of a diet for diabetics. He noted that certain carbohydrate-containing products are assimilated differently, and during the tests he was able to estimate the speed of their processing. The glycemic index of glucose, which is equal to 100 units, was taken as the absolute standard.
Who needs to know the glycemic index and what does it affect?
So what does the glycemic index affect? First of all, on the level of glucose in the blood. Entering the body with food, carbohydrates begin to digest in the digestive tract, and some even in the mouth.
There is their absorption through the mucous membranes into the blood, due to which it is saturated with glucose. Usually, the peak of glucose level is reached in about half an hour after a meal. And if its quantity grows too fast, then it can be dangerous.
The pancreas, which produces the hormone insulin, which is responsible for controlling the amount of sugar, can simply not cope. And if this body functions incorrectly, the threat will become very significant. And that is why it is extremely important to know the glycemic index in diabetes.
The use of foods with a high rate can lead to a sharp jump in glucose levels, which can have the most serious consequences.
What happens after the increase in glucose? As noted above, the pancreas begins to actively produce insulin, which provides a gradual decrease in the amount of sugar in the blood.
And it is this important organ that must determine where exactly the incoming glucose will go. It can go both to ensure the normal energy metabolism, that is, to the production of energy and to replenish its reserves, and in adipose tissue.
And it will depend on the amount of glucose and the quality of carbohydrates. So, if the level is high, then the pancreas just does not have time to adequately respond, and a part will still go "in reserve". The same thing will happen if the carbohydrates are simple and absorbed almost immediately. And all this means that knowledge of the glycemic index is important for weight loss.
What does it depend on?
The glycemic index is affected by several factors:
- Type of carbohydrates. All of them are conventionally divided into simple, digestible almost immediately, and complex, which are processed gradually. But such a classification is very conditional. In fact, they produce monosaccharides, disaccharides, oligosaccharides, polysaccharides, and fibrous carbohydrates. Monosaccharides are, in fact, one monomer that almost immediately penetrates into the blood, without being split and not being processed. This group includes the well-known glucose, fructose (sugar, which is present in almost all sweet fruits), galactose (this is a component of milk sugar, lactose) and some others. Disaccharides consist of two monosaccharides. These include lactose, maltose, lactulose, sucrose, isomaltose. Oligosaccharides are composed of a maximum of 20 monomers. This group includes galacto-oligosaccharides, fructo-oligosaccharides, and mannan-oligosaccharides. Polysaccharides can consist of tens, hundreds and even thousands of monosaccharides. These are chitin, starch, cellulose, dextrin, mannan, amyloid, and so on. Fibrous carbohydrates are also released, which are not digested at all, but have a positive effect on the body.
- The method of preparation, namely heat treatment. It is clear that the glycemic index increases significantly during frying. And, for example, popcorn has a higher rate than boiled corn.
- The content in the product fiber. This substance not only ensures the normalization of the processes of digestion, but also contributes to the control of blood sugar levels and even its reduction.
- The degree of industrial processing also has a certain impact. Thus, the glycemic index of refined rice is as much as 20 units higher than crude.
Glycemic index of certain products
The low glycemic index indicates that after consuming the product, the glucose level remains almost unchanged, and all carbohydrates that are ingested into the body will go to energy production.
It is this food that is recommended to be consumed with a diet, as well as with diabetes. Low is considered an index equal to 10-40 units. This group includes, for example, greens, most vegetables, sour berries and fruits, whole grains and dairy products (especially low-fat).
The average glycemic index ranges from 40 to 70 units. The group of such products includes dried fruits, sweet fruits, some legumes, cereals (corn, rice), potatoes, beets, and so on.
High glycemic index (over 70 units) is very dangerous for diabetics and harmful for losing weight. But sometimes it comes in handy, for example, after intensive training or physical exertion, when it is necessary to replenish the reserves of energy spent in a short time.
This group includes the following products: any sweets and confectionery, lemonade, most liquor, white bread, chips, canned fruits and many fried foods.
You can find out the exact values from special tables, which indicate the indicators of the most common products and dishes.
If you want to control the level of glucose in the blood or follow the figure, then by all means find out the glycemic index of the foods you use.
What is the glycemic index
Previously it was believed that foods with the same amount of carbohydrates have a similar effect on the growth of blood sugar. Long-term studies have revealed the fallacy of this belief. Then an indicator was introduced characterizing the speed of digestion of carbohydrates and the growth of glycemia during digestion in the gastrointestinal tract of a product. Called its glycemic index.
The increase in blood sugar after a meal depends on the type of carbohydrates prevailing in it. Monosaccharides are absorbed quickly, polysaccharides take much longer. The main source of energy in the human body is glucose. This is a simple carbohydrate monosaccharide, that is, consisting of a single molecule. There are other monosaccharides - fructose and galactose. They all have a pronounced sweet taste. Most of the fructose and galactose eventually turn into glucose anyway, some in the intestines, some in the liver. As a result, blood glucose is dozens of times more than other monosaccharides. When people talk about blood sugar, they mean it.
All other carbohydrates from food before splitting into the blood are also split into monosaccharides. The glucose will eventually become carbohydrates from the cake, and from the porridge, and from the cabbage. The speed of their digestion depends on the type of saccharides. With some, for example, with fiber, the digestive tract is not able to cope, so the increase in blood sugar during its use does not occur.
All patients with diabetes know that sweet foods affect blood sugar more strongly than the same cabbage. The glycemic index allows you to express this influence as a number. Glucose was taken as the basis for increasing glycemia, its GI was conditionally designated as 100. If a person without a problem with digestion drinks its solution, she will digest and quickly get into the blood. Glycemia, which is caused by all other products, was compared with glucose. Foods that have a minimum of carbohydrates, such as meat, received the lowest index of 0. Most of the other products were between 0 and 100, and only some of them increased blood sugar more strongly. For example, corn syrup and dates.
What is the GI and its criteria
So, we found out that the glycemic index is a conditional indicator. No less conditional is the division of GI into groups. The most commonly used classification approved by the WHO and the European Diabetes Association:
- low ≤ 55,
- an average of 55 50 must be considered high, and such products are completely excluded in case of diabetes.
According to the value of the glycemic index can be compared, as the same amount of carbohydrates from two products can raise blood sugar. We know that carbohydrates in cucumbers and black currants split and penetrate into the blood at about the same speed, their GI is low, equal to 15 units. Does this mean that eating 100 grams of cucumbers and currants will lead to the same glycemia? No, it does not mean. Glycemic index does not give an idea about the amount of carbohydrates in the product.
To be able to compare products of the same weight, use such an indicator as glycemic load. It is calculated as the product of the proportion of carbohydrates in 1 gram and GI.
- 100 g of cucumbers 2.5 g of carbohydrates. GN cucumber = 2.5 / 100 * 15 = 0.38.
- 100 g of strawberries 7.7 g of carbohydrates. GN strawberry = 7.7 / 100 * 15 = 1.16.
This means that strawberries will increase sugar more than the same amount of cucumbers.
Glycemic load is calculated per day:
- GN 120 - high load.
Healthy people are recommended to adhere to the average level of glycemic load, mainly to eat food with low and medium index. Patients with non-insulin dependent diabetes mellitus are recommended for low GN due to the complete elimination of products with high GI and restriction of food with medium GI.
Why it is important for diabetics to know GI products
Diabetics with type 1 disease with high GI are not prohibited if the patient is on intensive insulin therapy. Modern ultrashort insulin preparations allow you to choose the dose and time of administration of the hormone so as to fully compensate for the rapid rise in sugar. If a patient injects insulin according to the traditional scheme, he is unable to achieve consistently normal sugar, or insulin resistance is present, a glycemic index is imposed on him, only products with low and medium rates are allowed.
With type 2 diabetes is more difficult, patients with high GI are prohibited completely. Sweets are allowed only in the case of perfect control over the disease, and then in symbolic quantities.
Reasons for banning high glycemic index foods:
- Currently, there are no glucose-lowering drugs with such a fast action, so blood sugar will be elevated for some time, which means that complications will develop faster.
- The rapid flow of glucose provokes the same synthesis of insulin. With often elevated sugar and insulin, insulin resistance grows - the main cause of type 2 diabetes.
- When constantly high insulin stops the breakdown of fats in the body, all unused carbohydrates are deposited in the fatty tissue. Therefore, patients not only can not lose weight, but on the contrary, are actively gaining weight.
- Patients who prefer food with high GI, want to eat more often. Forming the feeling of hunger is the same excess of insulin.
Tables with GI Products Index
To determine which group a particular product belongs to, it is convenient to use tables in which all types of food are grouped according to the degree of growth of glycemia after they are consumed. At the top of the table - the most useful products from this point of view, below - those that will cause the maximum rise of sugar.
All figures are approximate. They were determined experimentally: they gave volunteers 50 g of glucose, controlled their sugar for 3 hours, calculated the average for a group of people. Then the volunteers received another product with the same amount of carbohydrates, and the measurements were repeated.
The data obtained may not accurately reflect the change in sugar in your blood, since the glycemia index depends on the composition of products, and on the characteristics of digestion. The error can reach 25%. If you notice that when you use one of the products, glycemia grows faster than from the others in the same line, move it a few positions below. As a result, you will receive a table of glycemic indexes that fully takes into account the individual characteristics of your diet.
Low Glycemic Products
Protein foods and fats contain a minimum of carbohydrates (0-0.3 g), so their glycemic index is zero. Low in almost all vegetables, legumes, nuts and seeds, some fruit. GI is in no way related to calorie content, therefore, in drawing up a menu for weight loss, this parameter should also be taken into account.
All varieties of dairy products are included in the safe group. For ordinary people, this is certainly healthy food, but in case of diabetes, their use should be coordinated with the doctor. The fact is that the glycemic and insulin index may not coincide. Biologically, milk is a product for young organisms that require excess insulin for rapid growth. Despite the low GI, it provokes an increased release of the hormone. With strong insulin resistance, when the pancreas is working for wear, dairy products are prohibited.
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Note: if the table does not indicate how vegetables and fruits are cooked, it is assumed that they are consumed fresh. During heat treatment or purirovanii glycemic index of foods will increase by several points.
In case of diabetes, the following list of products should be the basis of the menu:
What you need to know the glycemic index (VIDEO)
Glycemic Product Index - it is a popular indicator in modern medicine and dietetics that reflects how much a particular product enhances blood sugar. It was originally designed to control the nutrition of people who suffer from diabetes. But in the future, this parameter has become widely used in nutrition. Thanks to him, many diets have been drawn up for weight loss.
Exactly glycemic index will let us know how fast glucose from the product that we have consumed gets into the blood. The level of glucose is the main indicator of the amount of energy in the human body. So, when a person does not have enough energy, the level of glucose in the blood decreases, and the person begins to experience hunger.
If the level of glucose reaches a maximum, then the pancreas starts working, producing insulin - a hormone, due to which glucose is correctly distributed to the body tissues that need it, and its excess is deposited in the form of fat reserves.
If you want to lose weight or prevent weight gain, then you better follow the glycemic index of foods that you use. Avoid foods high glycemic index - These are fast carbohydrates, which cause a sharp jump in the level of glucose in the blood.
Therefore, when dieting it is important to consider not only calorie content products, but also such indicator as a glycemic index. Choosing products with a low index, you will provide the body with complex carbohydrates, thanks to which you will not feel acute bouts of hunger during the day and will be able to control your blood glucose level.
How does the glycemic index of foods affect the body?
The process of eating fast carbs and their effect on your body is as follows:
- The blood sugar level rises, reaching its peak after 30 minutes.
- The pancreas gradually begins to secrete the hormone insulin.
- The level of glucose along with this gradually decreases until it reaches a rate of 1 gram per liter.
- During insulin secretion, the pancreas determines where glucose should be sent - to normalize energy metabolism or to the fat depot. Where exactly the released glucose goes depends both on the health of the pancreas and on the origin of the carbohydrates (fast or complex carbohydrates).
Which groups are divided products depending on the glycemic index?
All carbohydrate-containing foods are divided into three large groups:
- Products with low GI (less than 40). Such products can be consumed indefinitely, they should be the basis of your daily diet. К ним, к примеру, относятся цельная пшеница, ячмень, рожь, бобовые, курага, кабачки, капуста, зелень, помидоры, молочные и кисломолочные продукты, горький шоколад и прочие.
- Продукты со средним ГИ (от 40 до 60) can be consumed in small quantities. These include oats, rice, buckwheat, corn, potatoes, beets, grapes, bananas, dates, and so on.
- Products with high GI (above 60) It should be limited in nutrition if you want to lose weight: white bread, biscuits, muesli, raisins, pumpkin, turnips, milk chocolate, lemonade, sugar, honey, beer, cakes, confectionery, and more.
- On degree industrial processing: the more processed the product, the higher its glycemic index. So, crude rice has a GI of 50, and refined - 70.
- On quantity fiber in the product: it is this which helps to reduce the level of sugar in the blood, and yes even has a number of useful properties.
- On how thermally the product was processed: GI of popcorn is higher than that of boiled corn.
- From the quality used Sahara: Fructose and lactose GI is much lower than glucose.
Glycemic Index: Myths and Misconceptions
Initially around glycemic index there was so much information that it contributed to the emergence of several misconceptions.
Myth number 1. It is necessary to completely eliminate foods with a high glycemic index from the diet. If the product has a high GI, you must also pay attention to the glycemic load - the amount of carbohydrates in one unit of volume. For example, a useful and tasty watermelon has a high GI, but at the same time a low GN.
Myth number 2. The glycemic index of the product is unchanged. This is not so, because the GI may vary depending on the method of preparation and heat treatment of the product. Try to choose the most thermally unprocessed foods - they should be the basis for the diet and snack foods.
Myth number 3. Cellulose does not affect the readings for GI. Fiber - dietary fiber - makes the product useful and nutritious. The more fiber in food, the higher its GI.
Myth number 4. To reduce GI, carbohydrates must be combined with proteins or fats. This is a rather controversial statement and is only partly true.
Glycemic Index and Sport
If you are actively engaged in sportsIf you regularly visit a gym, swimming pool or aerobics, it will be helpful for you to know which products have high glycemic index. The fact is that the athlete to achieve good results, you must correctly distribute the use of carbohydrates before and after training.
- Before exercise, it is better to use foods with low or medium GI.
- During training, high-GI products will help you quickly recuperate and significantly replenish energy reserves.
- In addition, products with high GI will help you to close the carbohydrate post-training window, thereby increasing its efficiency and replenishing the energy expended in class.
- In addition to GI after exercise, the amount of carbohydrates is important - it must be calculated from the amount of 1 gram per 0.5 kg of your weight.
We have already mentioned that glycemic load - This is an indicator that determines the amount of carbohydrates per unit volume of a product. In conjunction with glycemic indexThese options will help you choose the most appropriate products for your daily diet.
For example, take the products with equal glycemic index - watermelon (gi is 75) and donuts (gi is 74). If we consider that show GN donuts is 29.5 grams, and watermelon GN 6.6 grams, it becomes clear that along with donuts the body will receive much more carbohydrates than with watermelon.
Thus, if you are studying the basics of your diet and making up your daily diet, pay attention glycemic index and glycemic load, you will be able to most fully take into account the peculiarities of certain products, choose the dishes that suit you and eliminate empty carbohydrates that do not bring any benefit to the body. In addition, you will reliably protect yourself from such an unpleasant and dangerous disease as diabetes.