What feels good can not wrong: surprising in a study, the first of its kind, U.S. scientists emphasize that obesity affect people who eat without pleasure, while those who enjoy would be protected. 
Why? Because when a woman drinking a milkshake, for example, and the pleasure derived from it is insufficient, it compensates by eating more than a another who relish.
Witness the reading brain scans (MRI), by American scientists whose research is published in the latest issue of the journal Science.
"Over the milkshake taste is blunted, the greater your chances of gaining weight," says Dr Eric Stice Research Institute (Oregon), who led work.
A balanced diet and exercise are the main protective factors against overweight.
But scientists have long known that genetics plays an important role in the onset of obesity and that the culprit is probably the dopamine, a brain mediator who represents the key to feeling plaisir.Manger temporarily stimulates dopamine levels. brain scans suggest that the obese have fewer dopamine receptors in their brains than lean people .
And a particular gene variant, the Taq1A1, is correlated with fewer dopamine receptors. "
This article makes us one step" said Dr. Nora Volkow, the U.S. National Institutes of Health (NIH), dopamine specialist who has long studied the obesity link. "This work shows that the gene is associated greater vulnerability for obesity and asks the question why. How the brain works does it take to make a person more prone to compulsive eating and obesity? "Added the specialist.
reaching this observation, Stice team first sought to study the brain's immediate reactions to food front: move inside an MRI machine skews the measurements, which precluded the opportunity to drink their milkshake for women radiological examination.
Dana smalll, neuroscientists, has solved this problem by using a special syringe delivering directly into the mouth a small amount of milkshake or a neutral solution, to practice without consideration to the participants bougent.Les researchers then recruited volunteers: 43 female students aged 18-22 years and 33 adolescents 14 to 18.
According to the calculation of body mass index, the girls were very thin to obese . The brain scans showed that a key region, the dorsal striatum, the pleasure center rich in dopamine, became active when the guinea pigs tasted the milkshake, but not when they tasted the liquid neutral .
Yet that brain region was far less active in overweight people than in thin and those who have this genetic variant A1, the researchers said.
In addition, women who had this gene version were more likely to grow in the year .
This is a small study with few gene carriers, and it must be verified, said Volkow.Toutefois, it could have important implications.
Volkow, who heads the National Institute of Drug Abuse, notes that "dopamine is not used at pleasure." She plays a role in conditioning-dopamine levels affect drug addiction-and the ability to control impulsivity .
She wonders if instead of proving they eat to compensate for the lack of pleasure, which is the conclusion of Stice, the study does not show that people with malfunctioning dopamine in fact eat because they are impulsive.
Anyway, at the level of taste, most people tested find the tasty milkshake ... That reaction is subconscious brain.
If doctors can determine who owns the risk gene, children especially, so could be directed "towards sports or other that give them satisfaction and pleasure and dopamine, but that is not food ... and not to accustom their minds to bad food, "said Stice, a clinical psychologist who has long studied obesity.
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