You often hear about the glycemic index in advertising and in nutritional guides. But what exactly does the value say about food and how is it calculated?
Glycemic Index: This is what it represents
The glycemic index (GI) indicates how a carbohydrate-containing food affects blood sugar levels. The value tells you how high your blood sugar would rise if you were to eat a slice of bread, for example.
The higher the glycemic index, the more the blood sugar level is raised by a food.
In principle apply
Values above 70 as a high GI,
between 50 and 70 as medium high and
Scores less than 50 are considered low.
This is how the glycemic index is calculated
To calculate the value, the product is compared to the glycemic index of glucose. Our body can use this directly – it first has to break down other products into dextrose (glucose).
To calculate the glycemic index of a slice of bread, a test person must eat it. After that, your blood sugar level will be measured for two hours. The values are transferred to a diagram – they result in a curve.
Now the value of the area below the slice of bread curve is divided by the value of the area below the glucose curve. This quotient is multiplied by 100 and finally gives the glycemic index.
Don’t worry: you don’t have to calculate the GI of a product yourself. You can find the GI values for different foods in tables on the Internet. However, these are only average values that you can use as a guide.
The importance of the glycemic index
When we ingest carbohydrates, they first enter the intestines. There they are broken down into molecules and transported into the blood. The hormone insulin now ensures that body cells can absorb the sugar from the blood. The higher your blood sugar level, the more insulin is released.
Some carbohydrate-rich foods (such as white flour products and sweets) can be broken down faster than others. This often applies to products with a high glycemic index. They are used up faster by the body, making you hungry again soon.
On the other hand, if you eat foods with a low GI (e.g. whole grains and legumes), you will stay full longer. Such a diet can also help you to prevent obesity. In order to stay physically fit, however, you also have to consider other factors – for example, you should exercise regularly.
GI: An unbalanced diet can have these effects
If we consume a lot of carbohydrate-rich products with a high GI, this can have serious consequences:
It can cause your blood sugar to rise permanently.
According to the German Society for Nutrition, your cholesterol levels can increase more easily. You also have an increased risk of developing diabetes mellitus.
Research has also found a link between high blood sugar levels in women and obesity and coronary artery disease (CAD).
In order to eat healthily, you should avoid products that contain sugar. It is best to consume carbohydrates in the form of whole grain products, fruit, vegetables and legumes. Eat a balanced diet and include healthy sources of fat and protein in every meal.
Glycemic index for diabetics
The glycemic index can also play an important role for diabetics. Diabetes is characterized by chronically elevated blood sugar levels. If affected people mainly consume foods with a low GI, this can stabilize blood sugar levels and alleviate typical complicators.
The diabetes guide from the Apothekenumschau recommends integrating wholemeal bread and pasta, legumes, vegetables and many dairy products into your diet. However, diabetics should not base their diet solely on the glycemic index. Because a meal consists of different ingredients, this makes it difficult to calculate the GI.
What Factors Affect the Glycemic Index?
The value of the glycemic index is influenced by various factors. These include, for example:
Percentage of fat, protein and fiber in the food: All these components ensure that your body absorbs carbohydrates more slowly. As a result, the blood sugar level usually rises more slowly.
Degree of processing: How a product is prepared, how much liquid it contains and how hot it is can also affect the glycemic index. In general, the less processed a product, the lower the GI.
Meal composition: Other foods that you eat at a meal also affect blood sugar levels.
Individual Variations: Also, GI is not a universal value—how quickly a body breaks down glucose can vary from person to person. Blood sugar levels can also fluctuate depending on the time of day.
How exactly a meal ultimately affects your blood sugar level cannot be precisely determined by any value. Therefore, the importance of the GI is still highly controversial among scientists.
The glycemic load
The glycemic load (GL) magnitude was introduced as a supplement to the glycemic index. The percentage of carbohydrates in a food also plays a role in their calculation.
The glycemic load should always be taken into account because:
Carrots and baguettes have the same GI of 70, so the carbohydrates they contain have the same effect on blood sugar levels. Nevertheless, you can eat significantly more carrots to consume the same amount of carbohydrates. 700 grams of carrots contain 50 grams of carbohydrates, while 104 grams of a baguette would be sufficient.
For the GL, the GI is multiplied by the carbohydrate density value:
According to this calculation, the GL of carrots is around 5, while for baguette it is almost 34. The GL is therefore better suited to comparing carbohydrate-rich foods and assessing their importance for blood sugar levels. Despite this, the GI is still more widespread in everyday life.
