Lastly, even though sedentarity and nutrition are implied, heredity plays quite an important role in the risk, the gravity and the development of obesity.

Normally, a child puts on weight and grows steadily, whereas his fatty doesn’t follow the same evolution.

It increases a lot until one year old, decreases until six, before growing again.In the 90’s, an INSERM team showed that if this revival happens too early, at the age of three or four, later in life the child will be obese.

The establishment of the greatest world collection of families with obese children has allowed localising the sixth chromosome’s area, which predisposes to obesity.

There, we have found the ENPP1 (the Ecto-nucleotide Pyrophosphatase /Phosphodiesterase 1), an inhibitious gene from the insulin’s receptor, whose presence in a too high quantity in the liver leads to an insensitivity to insulin and to diabetes.

The discovery of this diabesity gene is very important, because it shows that beyond the eating perturbations, a kind of obesity related to diabetes and the metabolism exists. Then, a less insulin-resistant nutrition, or specific medicines could be very effective, in order to fight against the diabesity, the first epidemic with a non-infectious origin, in the story of humanity.

The excessive stoutness at the adult age provokes health problems, which are well-known today: diabetes, hypertension, cardiac or breathing diseases. This recognition of obesity as a disease has been done officially by the WHO, in 1998.

Some subjects, through a genetic inheritance, have lots of fatty cells (called adipocytes), but others can develop fatty cells by eating too much, which is a real problem as it won’t disappear.

On the one hand this excess weight is called hypertrophy, when it happens at the adult age and might be eliminated thanks to a good hygiene. On the other hand, when the adipocytes are excessively multiplied since the childhood, it is called hyperplasy.

It is then harder to fight against this excess weight, and concerned subjects will have to keep an eye on themselves all their life long.

The problem is that the body’s own mechanisms are against the loss of weight. Indeed, during the slimming, the adipose cell’s volume decreases, but it doesn’t disappear at all.

As these cells haven’t found enough fat reserve, it informs the brain, by increasing people’s eating quantity.

Nowadays, two medicines deal with obesity

The first one helps people to limit their nutrition quantity, and so fat’s absorption, at the intestine’s level.

The other one acts on the brain, in order to stop the eating quantity. It would be best if medicines could act on the reward’s system.

In a nutshell, obesity has always existed. Still it’s scale was different. In fact, now obesity is due to the changing ways of living. In the past, poor people worked hard and didn’t eat much: they were thin, whereas the upper-class were rich and fat.

Before the XVIII century, obesity wasn’t considered as a disease, it wasn’t a problem in the society: in fact, it just showed that you had good meals and you were wealthy.

That’s why we haven’t found many documents about obesity in the past (the studies about obesity only start in the beginning of the XX century). Moreover, the problem is differentiated according to the century. Until the XV century, there was no problem of allergy as the food wasn’t very diversified.

Then, after the Great Discoveries, there were lots of new foods, and a bad tolerance of metabolism could have bad effects.

Furthermore, the beauty criterion has changed a lot, and stoutness isn’t regarded as it was in the past. Next, obesity is essentially caused by heredity and genetical problems. Besides environment al factors are undeniably involved in people’s obesity.

Thus, during the last thirty years, children’s obesity has progressed everywhere like an epidemic. In Europe, in 2006, about one child out of three is overweight, and if nothing is done, most of them will be obese adults.

Nearly half of them will then develop diabetes and their life expectancy might be weaker than their parents.