[Article updated on 19/09/2023]

When we are interested in our diet, we seek to know the chemical elements which constitute our food and which we find in the nutritional sheets on the packaging.

Before reading on

I’m not an expert in this field, but I am passionate about nutrition and health.

The articles you’ll find on my site are the result of in-depth research that I’d like to share with you. However, I would like to stress that I am not a health professional and that my advice should in no way replace that of a qualified physician. I’m here to guide you, but it’s important that you consult a professional for specific questions or medical concerns. Your well-being is important. So be sure to consult the appropriate experts and take the best possible care of yourself.

We know sucrose, “white sugar”, cooking sugar; We are less familiar with a sugar, fructose, which is slipping more and more, without us paying attention, into our modern diet.

What is fructose? Should we be afraid of it or on the contrary can we adopt it without fear?

What is fructose?

Fructose is part of the carbohydrate family. It is a simple sugar (unlike starch, present in wheat flour, which is a complex sugar). Present in nature in fruits and honey, it is also found, but to a lesser extent, in vegetables and cereals.

In processed foods, it is found in maple syrup and agave syrup after concentration of the sap of these two plants.

Over the past few decades, it has appeared almost everywhere in our prepared dishes; it is used mainly in the form of wheat syrup or corn syrup in the manufacture of so-called “ultra-processed” foods such as sodas and fruit juices, but also soups, tomato sauces, condiments, marinades, preserves, breads , pastries, biscuits, etc. Manufacturers have adopted it for its “sweetening” qualities but also for other physicochemical properties (such as the coloring when baking pastries, etc.).


The number of calories provided by the fructose molecule is identical to that provided by other carbohydrates. On the other hand, its sweetening power is a little greater than that of sucrose (20% more, at least); it is stronger in an acidic environment, hence its success in sodas and processed fruit juices.

From a chemical point of view, when the fructose molecule is linked to the glucose molecule, they form the sucrose molecule (white sugar), present in nature in cane sap or in sugar beet root . During digestion, this sucrose molecule is hydrolyzed and produces one molecule of glucose and one of fructose. Fructose is present in our digestive system.

We hear that fructose has the quality of having a low glycemic index.

What is this glycemic index?

It is a medical indicator which measures the passage of glucose into the blood after the absorption of food.

The glycemic index varies on a scale from 0 to 100.

The element used to determine this scale is pure glucose which has a glycemic index or GI of 100. Pure water has a glycemic index of 0.

Fructose has a GI of 20.

Why does it have such a low GI? Because it must be transformed in the liver before passing into the blood while glucose passes directly.

Another particularity of fructose is that it does not trigger insulin secretion in our body.

Note that doctors monitor this insulin secretion because its dysfunction leads to an increasingly common disease: diabetes.

A question arises after these findings: is fructose good for health?

The number of calories provided by fructose is identical to that of other carbohydrates and its sweetening power, as we have said, is greater than that of white sugar, sucrose. We could, in theory, reduce our sugar consumption by using it.

But that’s false!

The concentration of glucose in the blood, called blood sugar, causes a feeling of satiety; we are less hungry, we will eat less.

The GI of fructose being much lower than that of glucose, by ingesting fructose as a sweet source, this feeling of satiety will appear later; we will have had time to eat more!

Another observation: it has been noticed, during medical experiments, that a diet rich in fructose leads to an increase in the level of triglycerides (fats) in the blood. It is said to have a hyperlipidemic effect, it increases the production of fats in the body

We also notice that a diet rich in fructose increases the level of uric acid in the blood, which causes the appearance of crystals in certain parts of the body, characteristic of gout or kidney stones.

In the United States, a country where fructose consumption is very high, in the form of industrial fruit juices, sodas, chocolate bars, ultra-processed breakfast cereals, ice cream, etc., studies have shown the link between their high consumption and the occurrence of symptoms such as dysfunction of insulin secretion (diabetes) and weight gain (obesity).

We therefore see that excess fructose is detrimental to health.

Let’s take an example: fruit juice

A priori, we could say that it is a food that is good for your health!

The fashion, imported from the United States, producer of oranges, of consuming fruit juice for breakfast has gained many followers in Europe. The orange is the ultimate healthy food full of vitamins. Yes, but…

We did a study which compared the consumption of the whole fruit on one side and the juice of this fruit on the other.

When we regularly consumed the whole fruit, the risk of diabetes fell by 1 to 26%, but when we only consumed the juice, the risk increased by 8%!


Ingestion of fiber contained in fruits and vegetables slows the absorption of nutrients in the body and therefore regulates the arrival of glucose in the blood.

Conversely, the absorption of fruit juice without fiber and therefore quickly assimilated, immediately increases the sugar level.

Is there an alternative?

Yes, smoothies!


They contain all the elements of the fruit but mixed. Of course, we do not have the advantages of chewing (release of food juices, natural cleaning of teeth and gums).

The ideal for smoothies is of course to make them yourself with a blender, or with an extractor (which will unfortunately eliminate a large quantity of fiber) or even a centrifuge. Quickly consumed, the nutrients in fruits are at their optimum; light and oxygen in the air destroy certain vitamins, time is a determining factor, you don’t make your smoothies for a week!

As for commercial fruit juices, nectars or smoothies, pay attention to their composition and especially the added sugars. The vitamins will be more or less preserved depending on the pasteurization method. Juices sold in the fresh section will retain more vitamins than those sold in the grocery-liquid section. Finally, note that many of these products are made from juice concentrates, so they are part of “processed” foods.

What we call fruit “nectar” comes from fruit puree, this process is used for fruits that do not produce juice (banana, apricot, guava, mango) In all these industrial products, fructose is abundant.

In conclusion, you must be careful with your consumption of fructose, which can be found in industrial foods in a hidden way. To do this, always look at the labels of the products you buy and consume minimally processed products as much as possible.