Functional MRI (fMRI) is rather like using Google Earth. It helps us to delve deeper into our understanding of how certain triggers activate centers in the brain associated with cravings and addictive behaviors. A recent study from Yale University published in Archives of General Psychiatry finds that women who completed a questionnaire that identifies substance dependence behaviors around food also responded to seeing and tasting a glass of chocolate milk shake. The reward centers were triggered by this cue just like cocaine in a drug addict. Maybe this is why it is so hard for people to diet – there are just too many cues around in our environment. Further studies will look at how much of this is learned rather than genetic. For most people it is probably a combination of both genes and environment.