Ah yes, the munchies: That oft-experienced, but barely-understood urge to chow down while indulging in whatever form of pot you choose. Now, research may have uncovered a key way that the munchies take hold: Pot could make us grab for the snacks by meddling with one of our neural "hungry" switches. The study, published online this week in Nature, looked at how cannabinoid receptors (activated by the psychoactive compound in weed and other compounds made by your own body) interact with neurons in the mouse hypothalamus. In both mice and humans, this is a small but mighty area involved in regulating a lot of important processes, including our hunger and sex drives. The researchers found that when they gave mice compounds that activated those cannabinoid receptors, the mice ate more. But, they also found that a particular bunch of neurons in the hypothalamus — the POMC-producing variety — had a lot to do with those munchies. This is somewhat surprising because previous work has shown that without the presence of cannabinoids, stimulating POMC neurons is usually associated with mice eating less. So, the study authors conclude that part of pot's appetite-driving effects come from its power to flip this switch in the "hungry" direction. Past studies have suggested a few other possible mechanisms for the munchies. For instance, pot may be altering our sense of smell, heightening our odor processing and thus our feelings of hunger. So, this new study is probably revealing just one of many mechanisms that combine to cause those cravings. Appetite is a complex, many-headed beast, after all. Although this work is perhaps most interesting to those with impaired appetite (such as cancer patients), the rest of us are curious, too, man.