Glycemic Index and Glycemic Load

The glycemic index and glycemic load are values ​​that show the influence of foods on blood sugar levels. Here you can find out how the values ​​are interpreted and what you should pay attention to.

Glycemic index and glycemic load for better blood sugar levels

The glycemic index and the glycemic load reflect the influence of a food on the blood sugar level and thus also on the insulin level. The glycemic index and glycemic load were developed to help people with diabetes make food choices. They are now used by many people who want to eat consciously. Even their own forms of nutrition have emerged from this, e.g. the Glyx diet or the Logi method.

The following applies: the higher the glycemic index and the higher the glycemic load, the greater the influence on blood sugar levels and the less well the food fits into a healthy diet. But it’s not that simple.

Which glycemic values ​​are good, which are bad?

The glycemic index and glycemic load values ​​are interpreted as follows:

Glycemic Index (GI):

• Low GI: 55 and below
• Average GI: Scores between 56 and 69
• High GI: 70 and above

Glycemic Load (GL):

• Low GL: 10 and below
• Medium GL: Values ​​between 11 and 19
• High GL: 20 and above

So if you want to limit your blood sugar levels as much as possible, you should choose foods with low values, although it is better to use the values ​​of the glycemic load (we explain why in the next section).

Of course, you can also eat foods with a medium GL or even high GL, just be careful not to eat too much of them or combine them with foods with a low GL. Because you usually don’t eat just one food, but a dish with different foods, so that this ultimately has a completely different GL than the individual foods and can therefore also have a completely different influence on the blood sugar level.

Better use the glycemic load

The problem with the glycemic index is that it doesn’t take into account the carbohydrate content in foods. It always refers to 50 g of carbohydrates, no matter how high the carbohydrate content of the food in question may be per 100 g. The glycemic load, on the other hand, refers to 100 g of the entire food, which of course makes much more sense.

It is therefore possible that a food has a high glycemic index and at the same time a low glycemic load – namely when the food contains only a few carbohydrates per 100 g.

The following example shows the difference on:

• A peach has a GI of 76. However, since it only has a low carbohydrate content of 9 g per 100 g, the influence on blood sugar levels is small. Therefore, the glycemic load is only 6.8: calculation GL = 76 x (9 g / 100 g) = 6.8
• White bread has a GI of 73. However, about half of white bread is carbohydrates (50g per 100g), so – despite the lower GI – it has a much greater impact on blood sugar levels than a peach. The glycemic load shows this clearly and is 36.5: Calculation GL = 73 x (50 g / 100 g) = 36.5

How foods affect blood sugar levels

If you are new to glucose metabolism, this section will provide you with the details so you can understand why the glycemic index and glycemic load are so interesting for a healthy diet.

This is how sugar is digested

During digestion, glucose from food is absorbed into the blood from the small intestine. The blood sugar level rises. This response is called the glycemic response. From the blood, the glucose is then distributed to the cells, since they need the glucose for their energy supply.

Glucose transport is controlled, among other things, by the hormone insulin, which is produced in the pancreas. As soon as the blood sugar level rises, the pancreas releases more insulin. The insulin level rises. As soon as the glucose is distributed from the blood into the cells, the blood sugar level begins to fall again. The body then signals hunger again and the cycle begins again.

The influence on the blood sugar level is so different

This is where the glycemic index and glycemic load come into play: If you eat a piece of white bread, for example, the blood sugar level quickly rises very high and the pancreas produces copious amounts of insulin to lower the blood sugar level again, because a permanently high blood sugar level is harmful and should be therefore be avoided.

On the other hand, if you eat a peach, the blood sugar level does not rise as high, which means that the pancreas has to produce less insulin, the blood sugar level falls more slowly and the feeling of satiety lasts longer. So the peach has a low glycemic load, while white bread has a high one.

With a high glycemic load, the risk of diabetes increases

It is known that a high-sugar diet can increase the risk of diabetes. But there are foods that increase the risk of diabetes even though they don’t appear to contain any sugar, such as mentioned white bread.

With the help of the values ​​from the glycemic load and glycemic index, it is easier to see which foods are problematic in this respect and which are less so.

Eating foods with a high glycemic load can promote insulin resistance. If there is insulin resistance or insulin deficiency, not enough glucose gets into the cells and the blood sugar level remains permanently high – this is referred to as diabetes.

Low-glycemic foods improve diabetes

Conversely, low-glycemic foods, i.e. foods with a low glycemic load or a low glycemic index, can improve existing diabetes again.

In a 2019 review, researchers took a closer look at a total of 54 studies on this topic. They concluded that a diet high in low-GI foods had a positive effect on fasting blood sugar, BMI (body mass index), and cholesterol levels in people with diabetes.

The researchers write that the effects were generally small, but that drugs had only a small effect on the fasting blood sugar level.

The effects on fasting blood sugar levels were also greater the longer the studies lasted, i.e. the longer the test subjects ate a low-glycemic diet. Seven of the studies lasted longer than six months.

Whether low GI foods also help you lose weight has been a matter of debate. There are studies that found a positive effect, but also those that could not find any connection.

The list: glycemic index and glycemic load

Foods with a low glycemic load

Have a low glycemic load:

• fruit
• vegetables and salads
• legumes
• nuts
• dairy products
• meat, fish and eggs.

Foods with a high glycemic load

Foods with a high glycemic load include:

• sugared cornflakes
• chips and popcorn
• chocolate bar
• sugared soft drinks.

Glycemic index and glycemic load can vary widely

The GI and GL values ​​can vary greatly depending on the composition, processing, degree of ripeness, variety and preparation of a food. It often even depends on the brand or the country of origin, how high the GI or the GL of a food or product is. The values ​​in our list above are therefore always average values ​​for rough orientation.

Here are some examples:

• Mashed potatoes have a higher GI (GI: 79, GL: 11) than whole cooked potatoes (GI: 73, GL: 10) because the carbohydrates in mashed foods are more easily absorbed. The GI is also reduced when the potatoes cool down (GI: 49, GL: 7), as part of the digestible starch is converted into indigestible starch.
• Potatoes of the Nicola, Bintje and Desiree varieties have a higher GI than potatoes of the Carisma variety.
• A ripe banana has a GI of 47, an overripe banana has a GI of 57.
• Whole grain bread has a lower GI than white bread. The same goes for rice: brown rice has a lower GI than white rice.
• A soy drink of the same brand has a different GI depending on the flavor (chocolate GI: 40, vanilla GI: 28, original flavor GI: 15).
• Kellogg’s Muesli Special K has a GI of 69 in the USA but a GI of 84 in France.
• Dreamrice brand basmati rice from Singapore has a GI of 56, and Laila Basmati Rice brand basmati rice from the United Kingdom has a GI of 66.

Diets based on the glycemic index

The concept of the glycemic index, which was introduced in the 1980s, has given rise to numerous forms of nutrition, which we provide an overview of below. Glycemic load was also developed later. Of course, the same problems as with the GI also apply to the forms of nutrition based on it.

The Glyx Diet

The Glyx Diet favors low GI foods and avoids high GI foods. The goal of the Glyx diet is a permanent change in diet and weight reduction, which should result from the reduced feeling of hunger.

The blood sugar level should remain as constant as possible – in addition, fatty foods should be avoided. If fats are used, then those from meat and fish.

The Montignac method

The Montignac method is a mix of a Glyx diet and food combining. All carbohydrates with a GI above 50 are banned from the diet. Carbohydrates with a GI between 35 and 50 should also not be combined with fat. According to founder Michel Montignac, the reason for this is that the fat is stored more easily due to the increased blood sugar and insulin levels. Carbohydrates with a GI below 35, on the other hand, can be mixed and matched as you like, since they only slightly increase blood sugar levels.

The Montignac method is not a diet in the classic sense, but a form of nutrition. Montignac assumes that it is not the amount of calories that is the cause of obesity, but high insulin levels.

The South Beach Diet

The South Beach Diet also evolved from the Glyx Diet. In the first two weeks, carbohydrates are completely avoided – instead, more proteins are put on the plate. Then low GI carbohydrates are slowly reintroduced. This diet also aims to change your diet. The fat and protein content are each 40 to 45 percent, with vegetable fats being preferred.

The Logi method

Logi stands for “Low Glycemic and Insulinemic Diet”. The Logi method is a mixture of low-carb and Glyx diet, which aims at a low blood sugar level and low insulin release.

The Logi method does not focus on losing weight, but on improving blood values ​​by reducing carbohydrates. The meat content and the fat intake are quite high, but even whole grain products are only eaten in small portions. The diet was originally developed for people with insulin resistance.

Mediterranean diet and whole foods

There are also diets that are not based on the concept of the glycemic index, but naturally consist of foods with a fairly low GL:

The traditional Mediterranean diet focuses on fruit and vegetables, legumes and whole grains, while eating little dairy, fish and meat.

Whole food nutrition or whole foods is also naturally low in high GL foods as fresh, unprocessed foods and whole grains are preferred and lots of vegetables and fruits are on the table.

Conclusion: The glycemic index and the glycemic load

The glycemic index and glycemic load help identify foods that negatively impact blood sugar levels. However, the two values ​​can also be misleading as they do not equate to whether a food is healthy or not.

Foods with the highest glycemic index include potatoes, bread and rice, while dairy products, legumes, many vegetables and energy bars for athletes are among the foods with the lowest glycemic index.

Of course, foods such as potatoes still have health-promoting properties, while e.g. dairy products and energy bars do not necessarily have to be healthy.

In addition, the values ​​can vary greatly, making it all the more difficult to calculate the glycemic load of entire meals. When choosing your food, you should never rely solely on the glycemic index or glycemic load.

However, the glycemic load can provide a good indication of which foods fill you up in the long term and only have a minor effect on blood sugar levels. It thus represents one of many criteria for the choice of food.