Food on the brain
26 January 2009
By showing people pictures of appetising or bland food, researchers at the MRC Cognition and Brain Sciences Unit and the University of Cambridge have shown that the brain's response to food differs in people who are prone to overeating from that of people who are at a lower risk of obesity.
"The differences in brain responses observed may explain why some people are highly vulnerable to the power of food advertising," says Dr James Rowe, one of the study's authors.
The research involved 21 men and women who completed a questionnaire to establish their eating behaviour. They fasted for two hours and were then shown alternating images of appetising high-calorie sweet food such as cream cakes, or bland food such as plain rice or pasta. Functional magnetic resonance imaging (fMRI) was used to monitor brain activity, by measuring blood flow in the brain.
"The subjects were not asked to choose between these foods. What we're interested in is how the brain is responding automatically to the sight of food", says Dr Rowe.
The study found that, as people react to the sight of appetising or bland food, the brain network associated with feeding in animals is automatically activated. The areas of the brain involved include those linked with the reward aspect of eating.
Strikingly, in people who are able to resist unhealthy food, the brain's food network is very highly connected in response to enticing food. People who are more likely to overeat show a less well-connected network when seeing appetising food.
"If you are highly sensitive to images of palatable food then your brain networks respond differently to appetising and less appetising food, even in the absence of hunger", says Dr Rowe. The activity of the brain's feeding network in telling the difference between cream cakes and plain rice may go part way to explain the rise in obesity.
References
Passamonti L et al. Personality predicts the brain’s response to viewing appetizing foods: the neural basis of a risk factor for overeating. J Neuroscience 2009;29(1):43-51.