14 DAY TRIAL // Researchers at the University of Cambridge found that an anti-obesity drug, called sibutramine, actually works, because it changes the way that the brain responds to appetizing, high-calorie foods.
This discovery might just be the first right step towards developing an efficient anti-obesity drug, that would simply reduce the impulse of over-eating, triggered by the sight of tasty foods.
Professor Ed Bullmore, from the Department of Psychiatry at the University of Cambridge and director of the GlaxoSmithKline (GSK) Clinical Unit in Cambridge (CUC) said that “the major cause of obesity in the West is over-eating, and this behavior is regulated by reward and satiety processing circuits in the brain.”
So the researchers used functional magnetic resonance imaging (fMRI) to measure the brain activity of obese volunteers who were watching images of tasty, high-calorie foods – like chocolate cake, or low-calorie foods, like broccoli.
Two other brain scans were carried out both after two weeks of sibutramine treatment, and two weeks of placebo treatments.
The results of the scans showed that in the case of placebo treatments, many regions of the brain that are known to be linked to the reward process, were activated by the simple sight of appetizing foods.
Sibutramine on the other hand, was found to reduce brain responses in two regions of the brain, which are important for appetite control and eating behavior – the hypothalamus and the amygdala.
Also, volunteers under sibutramine ate less and managed to lose more weight.
“Currently, there are few drugs that effectively help patients to lose weight,” said Professor Paul Fletcher, from the Department of Psychiatry and the behavioral & Clinical Neuroscience Institute at the University of Cambridge and one of the paper's authors.
“Developing new pharmaceuticals is expensive and risky, however, our findings suggest that we may be able to use brain imaging and psychological tests to make better predictions of which drugs are likely to work.”
Professor Ed Bullmore added that these “results help us to understand more precisely how anti-obesity drugs work in the brain to change eating behavior and hence, ultimately, to assist people in losing weight.
"The most exciting aspect of these results is that they help us to see that brain and behavior are fundamental to understanding and treating obesity.
“Simply because obesity involves major changes in body weight and body composition, it is easy to imagine that it is entirely 'a body problem'.
The results of this research are reported today in The Journal of Neuroscience.