Glycemic Index of Foods

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(GI) represents the ability of carbohydrates contained in food to raise blood sugar (a value that indicates the amount of glucose present in the blood). To quantify the glycemic index of a food it is necessary to take 50 grams and monitor the glycemic levels in the following two hours. These values ​​will then be compared with those of the reference standard which in this case is glucose or white bread (glycemic index = 100 If a food has a glycemic index of 60, it means that by ingesting 50 grams of that food, the blood sugar rises by 60% compared to what happens with 50 grams of glucose or white bread.

Generally speaking, the more digestible a carbohydrate is, the higher its glycemic index will be.

• Not all carbohydrates are created equal:
  
  • some are absorbed quickly and lead to a rapid rise in blood sugar (high GI)
  • others release glucose more slowly (low GI).

When it comes to the glycemic index, it is also very important to specify the concept of GLYCEMIC LOAD.

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This parameter is obtained by relating the glycemic index of a certain food to its average portion. It is therefore sufficient to multiply the GI of a given carbohydrate (eg fructose IG = 20) by the quantity taken (for example 30 grams). specific case the glycemic load of the meal is equal to 20 x 30 = 600.

In order not to gain weight and to keep glycemic and appetite under control, the quantity of what you eat is therefore more important than the glycemic index of the individual food. Excluding some foods from your diet just because they have a high glycemic index makes no sense, just, simply , have a balanced relationship with food, avoiding excesses.

The following table shows the glycemic index of some foods belonging to different groups. For easier identification we have divided the foods into three classes (high, medium and low glycemic index).

109 Pineapple 59 ± 8 Prune 39±15 Dates (dried) 103±21 Ice-cream 57 to 80 Apricot 38 ± 2 Maltodextrin 100 Kellogg's Special K 54 to 84 Pears 38±2 Glucose 100 Muesli 39 to 75 Fish sticks 38 White bread from 30 to 110 Coca Cola 58±5 Yogurt 36 ± 4 Cornflakes (Kellog "s) 91 Barilla Spaghetti cooked 10 minutes 57 Boiled peas 32.9 Honey 32 to 95 Banana 52 ± 4 Low-fat milk 32 ± 5 Baked potatoes 89±12 Kiwi 53±6 Soya milk 32±2 Cheese pizza (Italy) 80 Mango 51±5 Canned Peaches 30 to 71 Gatorade 78±13 Rye bread 50 to 64 Boiled beans 29 ± 9 Frum bread. gluten free 76±5 Pineapple juice 50 ± 4 Fresh peach 28 to 56 French fries 75 Grapefruit juice 48 Apple 28 to 44 Pumpkin 75 ± 9 Macaroni 47±2 Sausage 28 Crackers 52 to 98 Carrot 47 ± 16 Whole milk 27 ± 4

Melon

75 Grape 46 to 59 Cherries 22 Watermelon 72 ± 13 Canned Pears 46.0 Lentils 22 to 34 Popcorn 72±17 Low-fat fruit yogurt 45 Pure fructose 19 ± 2 Arborio rice 69 ± 7 Orange 42 ± 3 Boiled Soy Beans 18 ± 3 Fanta 68 ± 6 All-Bran 42 ± 5 Light yogurt 14 to 45 Sucrose and cane sugar 68 ± 5 Apple juice 40 ± 1 Peanuts 13 Croissant 67 Biscuits (Oro Saiwa, Italy) 64±3 Common boiled potatoes 56 to 101 Sweet potatoes 61 ± 7

**NOTE:

When it comes to the glycemic index of a food, it is important to define a range of values ​​that takes into account all those parameters that can influence it positively or negatively. The glycemic index of a food varies, for example, with:

• its degree of ripeness (it increases if the fruit is well ripe)
• the variety (green "diabetic" apples do not have the same GI as red ones)
• cooking temperature and time (increases with heat)
• the shape of the pasta
• the quantities of ingredients used (especially in the case of industrial products)

For all these reasons, it makes little sense to propose an average value that could deceive the consumer, leading him to make incorrect food choices.

instead of fats; the transformation of sugar into fat also tends to increase (overweight);

oxidative stress increases (premature aging, cancer risk);

after 2-4 hours the blood sugar drops and hunger returns;

over time an overload of work is created for the pancreas which initially causes insulin resistance and subsequently the onset of diabetes;

the risk of tooth decay is greater.

A diet too rich in foods with a high glycemic index (high overall glycemic load) increases the risk of cancer especially in the gastrointestinal tract and ovary. It is not yet clear whether this relationship is due to excessive consumption of high GI foods, the resulting overweight, or to a diet that is too high in sugar and low in fruit and vegetables.

For the athlete it is important to avoid taking too many high-glycemic index foods before competition or training. In fact, the consumption of simple sugars would rapidly increase blood sugar by stimulating a prompt secretion of insulin with consequent secondary hypoglycemia, decrease in fat oxidation and possible rapid depletion of glycogen stores.

Carbohydrates with a high and moderate glycemic index, on the other hand, are useful for promoting recovery after training.

as they attenuate postprandial hyperinsulinemia and promote an increase in good cholesterol (HDL).

It is interesting to note that the glycemic index of food does not depend only on the type of carbohydrates it contains. Rice and potatoes, despite being rich in starch (polysaccharide), have a higher glycemic index than fructose and many sugary fruits. In fact, dietary fiber slows down the gastric transit time, with a reduction in the speed of absorption of the sugars taken together with the fiber. A similar argument can be made for fats (skimmed milk has a higher glycemic index than whole milk) and to a lesser extent for proteins.

The consumption of low glycemic index foods before the competition has a positive effect on the performance of athletes.