- Glycemic index and glycemic load
- How to know the glycemic index of foods
- Glycemic index to improve training
The glycemic index is an indicator of the speed with which the carbohydrate in a food reaches the bloodstream and changes blood glucose, which is the blood sugar level. Thus, foods with a low glycemic index, such as beans, pears and oat bran, keep blood glucose in check for longer, delaying the onset of hunger after a meal.
From the glycemic index values, foods are classified into 3 categories:
- Low GI: when the glycemic index is less than or equal to 55; Medium IG: when the glycemic index is between 56 to 69; High GI: when the glycemic index is greater than or equal to 70.
For the classification of the main foods, see the complete table of glycemic index of carbohydrates.
It is important to remember that the glycemic index is only applied to foods that are mainly composed of carbohydrates, such as cereals, pasta, sweets, rice, potatoes, fruits, dairy products and vegetables, and does not exist for foods based on proteins and fats, such as meats, eggs, olive oil and butter, as they do not alter blood glucose.
Glycemic index and glycemic load
While the glycemic index corresponds to the speed with which the carbohydrates in the food increase blood sugar, the glycemic load is linked to the amount of carbohydrate present in the food: the more carbohydrate, the greater the change in blood glucose.
The classification of glycemic load is made as follows:
- Low glycemic load: values up to 10; Average glycemic load: values from 11 to 19; High glycemic load: values from 20.
The glycemic load is important because not always a food with a high glycemic index will be able to change blood glucose in a bad way. For example, watermelon has a high glycemic index and a glycemic load of only 4, which means that a slice of watermelon does not have enough carbohydrate to raise blood sugar too much.
How to know the glycemic index of foods
To be more sure about the value of the glycemic index of foods, you should look at the table, but the following tips are useful to assess whether a particular food has a high or low glycemic index:
- The more cooked or more processed a food is, the higher its glycemic index: juices have a higher glycemic index than whole fruits; mashed potatoes have a higher glycemic index than whole cooked potatoes; the more ripe a fruit or vegetable is, the higher its glycemic index; fruits and vegetables in their skins have a lower glycemic index than peeled ones; the longer a food is cooked, the higher the glycemic index: an al dente pasta has a lower glycemic index than a well-cooked pasta.
Thus, a good tip to avoid foods with a high glycemic index is to consume food in the most natural way possible, consuming fruit and vegetable peels whenever possible and avoiding industrialized products. See examples of low glycemic index foods.
Glycemic index to improve training
Before training, you should consume foods with a low to moderate glycemic index, such as bananas and sweet potatoes, as they will raise your blood sugar slowly, giving energy to the moment the training begins.
If the physical exercise is intense and lasts more than 1 hour, you should consume carbohydrates with a high glycemic index to quickly replenish your energies for training, and you can use carbohydrate gel, isotonic drinks or fruits with a higher concentration of sugar, such as the prunes.
After physical activity, the athlete must also prioritize the consumption of foods with medium to high glycemic index, to replenish carbohydrate stocks and accelerate muscle recovery. See more about how to use the glycemic index to improve your workout and see examples of meals in this video:
