Reward centres of obese women act differently to those of normal weight

A new study has shown that the parts of the brain that control feelings of reward continue to respond after severely obese women are already full.  The brains of 15 obese women were compared with the brains of 15 lean women. It was found that activity in certain parts of the brain were increased in both groups before a meal, whilst they were hungry, however after the meal these centres continued to respond in the obese women. Whilst the appeal of pictures of food dropped by 15% for lean women, the obese women only had a 4% drop, further to this the reward centres in the obese women’s brains maintained activation.

The authors of the study described the obese women as having ‘an instinctive drive to keep eating’. These findings may help to explain why some obese people report underlying and irresistible drives to continue eating, despite the fact that they are no longer hungry. This also highlights some of the more difficult factors to address when attempting to treat obesity in a handful of the population.