There are several problems with this article: the first is that there is no meaningul definition of what constitutes "junk food." In my opinion, there is no need to define "junk food" as I have never seen convincing evidence to suggest that an equivalent caloric amount of "junk food" promotes obesity more than the same caloric amount of "natural" or "healthy" food. In this contentious area, journalists and anti-obesity advocates frequently complicate the obesity issue by diverting attention away from the core issue --excess net calorie intake -- and focusing on irrevelant issues, such as "junk food." Another major claim of this paper -- that the fact that ghrelin (which is a physiologic hormone that promotes hunger) acts on similar parts of the brain as addictive substances suggests that we should consider regulating "junk foods" -- makes no sense. Firstly, it is not at all surprising that we would be hard-wired to be "addicted" to food, since food is required for life. For example, if oxygen deprivation caused activation of similar addiction-associated brain pathways, would that mean that we are "addicted" to oxygen and therefore it should be regulated by the government?Furthermore, is there any evidence that "junk food" produces higher gherlin levels than "healthy food"? I think this whole basic discussion of regulating "junk food" is fundamentally flawed and simply acts to obscure the fundamental issue: eating too many calories (either "junk" or "healthy") without enough compensatory exercise produces obesity.