Leptin levels fall as obese individuals lose weight. So, the authors set out to see whether changes in leptin levels altered activity in the regions of the brain known to have a role in regulating food intake.
They observed that activity in these regions of the brain in response to visual food-related cues changed after an obese individual successfully lost weight. However, these changes in brain activity were not observed if the obese individual who had successfully lost weight was treated with leptin. These data are consistent with the idea that the