Between the traditional morning tea or coffee, the little treats we enjoy most days and then the industrially prepared meals, sugar is everywhere in our food. 

Scientific data shows the harmful effects on health of excess sugar consumption. Excess weight, metabolic problems with an explosion in the number of cases of diabetes, inflammatory diseases, cardiovascular diseases, tooth decay… With the irresistible urge to come back for more again and again...

This "sugar mania" is also fed by the food processing industry, most often without our knowledge.

It is a public health issue that led the World Health Organisation (WHO) to issue a recommendation in March 2015 that free sugar in food should be limited to below 10% of daily energy intake (50 grammes or 8 sugar cubes).

Simple or complex sugars? Slow, fast?

Historically, we distinguish between "simple" sugars, small in size and made up of three sugar units, and "complex" sugars which result from the chaining and branching of many simple molecules.

So, for a long time we thought of simple sugars as being rapidly degraded by digestive enzymes, hence their name fast sugars, as opposed to complex sugars, digested more slowly due to their large size, therefore considered to be slow sugars.

However, it would be more appropriate to classify sugars according to their glycaemic power, in other words their ability to alter blood sugar levels and insulin secretion.

This is why the notion of the glycaemic index was created:

  • Glycaemic index > 60= high glycaemic index= large release of insulin= fast sugar
  • Glycaemic index < 40= low glycaemic index= small release of insulin= slow sugar

Finally, each sugar is allocated a sweetening power, reflecting its ability to produce a sweet taste.

Name Base components Sweetening power Glycemic index Source - where is it found?
Glucose  70 100 Bread, biscuits, sauces, energy drinks.
Fructose  110 20 Drinks, ice cream, biscuits, jam, industrial bakery products.
Galactose Galactose 30 40 Milk and dairy products.
Fructose + glucose 100 70 Sugar extracted from cane or beet. Table sugar, preserves, desserts…
Lactose Glucose + galactose 30 40 Milk and dairy products.
Glucose + glucose 43 105 Preserves, jam, beer, ketchup, sweet potatoes.
Starch 600 < 
< 1000
None 85-100 Cereals, legumes.

Sugar: sometimes hidden, but always omnipresent

In the 1960s sugar was mostly consumed as saccharose (60% to 80%) in powder or cube form and added to food; "home made" was the order of the day. Sweet foods generally formed part of traditional celebrations such as Shrove Tuesday, Easter, Christmas and New Year. As society evolved, its use was magnified by certain restaurants and high-profile chefs using high amounts of sugar...

Industrially prepared foods and meals then became more and more common, from breakfast to main meals and snacks enjoyed by young and old alike! And this is the crux of the problem: sugar has been slipped in just about everywhere, of course into sweet-tasting products but also into others that are not sweet to the taste (soups, bread, pickles, savoury biscuits, ketchup, cooked meats, sauces, salad dressing, balsamic vinegar, stock cubes, crispbreads, prepared meals, frozen foods...).

Almost our entire current sugar consumption (80%) comes from processed foods, most often in the form of glucose, fructose or glucose-fructose syrup.

Hunting down the sugar: decoding food labels!

Sugar comes in dozens of different names.
First look out for terms ending in '-ose', including syrups (see table above).

And here are some other names for sugars: sorghum syrup, maple syrup, carob syrup, corn syrup, date syrup, starch syrup, agave syrup, cane juice, cane juice crystals, grape sugar, coconut sugar, malt extract, diastatic malt, diastase, modified starch, molasses, dextrin, dextran, maltodextrin, fruit juice, grape juice, apple juice, muscovado.

And, of course, honey and caramel.

From pleasure... to addiction

To enhance the taste or to preserve, soften, crispen, colour, improve texture, ferment... industrial producers believe the addition of such sugars to be indispensable. Could it also be to make us want more? It has been demonstrated that the more we consume sugar, the less reactive become the dopamine receptors on which it acts to give us the pleasurable sensation; so we need higher quantities! This is added to the fact that sugar has a turbulent effect on our glycaemia, or blood sugar level, producing the well-known "hypo effect" when it suddenly drops down again producing a feeling of dizziness and sugar cravings. A vicious circle!

Our body is unable to handle excessive consumption!

The main source of energy for our cells, glucose (and not sugar), can be considered to be the body's fuel. Under the action of digestive enzymes, carbohydrates lead to the formation of glucose, fructose and galactose, the latter two of which can also give rise to glucose. 

After a meal, glycaemia, or blood sugar level, increases and causes the release of insulin, a hormone produced by the pancreas. Its role is to transport blood glucose to the cells of the muscles and liver and to the fat cells where it is used. This helps regulate blood sugar levels.

But too much glucose disturbs the metabolism. When the cells are constantly subjected to high doses of insulin by high glucose intake, they react and the number of insulin receptors decreases on their membranes: it is called "insulin resistance". The pancreas must produce more and more insulin for glucose to be used ... In the long run, type 2 diabetes develops with a high level of sugar in the blood with deleterious effects!


Fructose is metabolised very differently from glucose: its processing by the liver leads to the formation of uric acid and produces enzymes that promote the production of triglycerides in the blood (a risk factor in atherosclerosis), the increase of fat in the liver (risk of steatosis or "fatty liver") and fat storage, notably in the abdomen. Chronic consumption leads to hypertension, to insulin resistance much faster than with glucose, weight gain and even obesity, metabolic syndrome, diabetes and stimulates the reward system leading to the desire to eat more.

What about fruits

Fruit also contains fructose, as do beans and pulses, but consumption is nevertheless recommended!

When you eat fruit, beans or pulses, the absorption of fructose by the intestine is significantly slowed down by the fibre. They also contain naturally beneficial antioxidants and phytonutrients. The maximum content of fructose is an average of 10g for fruit and 4g for beans and pulses. So it is not possible to exceed the liver's capacity to metabolise fructose from fruit, beans and pulses.

The danger actually lies with the intake of fructose that is added to food, in other words in forms that are not natural. So we should limit or even eliminate consumption of fizzy drinks, iced teas, energy drinks..., preserves, jam, biscuits, prepared foods… but also fruit juices and compotes which no longer bear any resemblance to fruit and with which the fructose is digested very rapidly.

Be careful also of agave syrup and coconut syrup which mainly consist of fructose.

Sugar and health

Numerous studies have shown the harmful effects on our body of excess sugar. Here are the main ones.

Find out more

The journalist from ELLE magazine specialising in health and wellbeing tested out a sugar-free diet lasting one year.
Personal testimony, surveys and practical advice. A mine of information. A really good read.

Zéro sucre
Danièle Gerkens
Editions Les Arènes • april 2015

To reveal the hidden sugar in 1,500 foods. An essential book

Le compteur de glucides
Magali Walkowicz
Editions Thierry Souccar • april 2015