Obesity: Addicted to food
All content is checked by medical journalists.People who are overweight often torment themselves with diets or exercise in order to lose extra pounds. But again and again she was overwhelmed by the desire to eat and all efforts were in vain. Brain scans are now providing clues as to why this is so: Especially those who carry around extra pounds seem to have brain structures that make them crave calorie-rich food more than others.
Experts believe that the reward system in the brain of overweight people gives them a particularly strong signal that food is a very special pleasure.
Illuminated brains
Oren Contreras-Rodriguez from the Bellvitge Hospital in Spain and her colleagues examined 39 overweight and 42 normal-weight men and women and examined their brains. Before the examination, the subjects were allowed to feast at a buffet. Their eating behavior was observed - especially the consumption of high-calorie food.
The researchers then showed the participants photos of various foods and recorded their brain activity in a functional magnetic resonance tomography (fMRI) - a body scanner - in the meantime. Regions that were stimulated by the photos shone particularly brightly. The researchers were mainly interested in the connection between the various brain areas.
Brain activity like addicts
As expected, brain regions glowed differently in overweight and normal weight people - they were differently active. The reason: the reward system reacted more strongly to the visual food stimuli in overweight participants than in those of normal weight. This suggests that overweight people have greater rewards than eating for people of normal weight, which is why they feel an increased need for food, according to the scientists.
The links between different brain areas also differed depending on the weight of the test subjects. In the case of overweight participants, the regions of the brain that, for example, take in visual impressions of food and those that become active during pleasure, among other things, were more closely linked. The same phenomenon has already been seen in addicts when they saw their drug.
Researchers predict weight gain
Using the brain scans, the scientists made statements about the future weight changes of the participants. And indeed, measurements of the body mass index three months later confirmed that the weight changes in the already obese participants could be predicted with the help of the well-known brain signature.
However, it remains unclear how the altered brain activity and the urge to eat fit together. So far, the researchers have been able to establish a connection - but have not yet proven whether the altered brain signature causes the urge or, conversely, increased food consumption leads to altered brain activities. The researchers hope that neuronal traces in the brain can be used in the future to help severely overweight people lose weight.
Dangerous fat
Obesity is more dangerous than many people think: thousands of people die every year due to obesity and secondary diseases such as diabetes or fat metabolism disorders. For several years, experts have classified obesity as a chronic disease.
The body mass index decides to which weight class - underweight, normal weight, overweight or obesity - a person belongs. It is calculated from the ratio of height and weight.
Source: O. Contreras-Rodríguez et al. Brain correlates of the desire to food predict body mass index change in excess weight adults. Annual Congress of the European College of Neuropsychopharmacology. 2015.
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