With the exception of a Spanish-speaking Chihuahua, there are probably few things that drive Taco Bell business better than marijuana. But why does that happen? Because the munchies are real and neuroscientists think they know why. Cannabinoids, the active compounds in marijuana take your neurons on a joy ride. POMC neurons are responsible for, amongst other things, making you feel full by sending a chemical signal to your brain. The researchers injected cannabinoids into mice and discovered two effects on the POMCs: Increased activity and a reversal of function. Instead of letting your brain know its time to cool it with the Doritos Locos Tacos, the neurons released endorphins, which trigger appetite.
As with many studies, there's a caveat: The scientists performed this experiment on mice, not people. But the area of the brain they studied is actually quite similar in humans and mice. Similar enough that the study’s leader, Yale scientist Tamas Horvath, told NPR he would “bet his life” that the findings would hold in people.
While pot has other effects on the brain that might make someone eat more—increasing sensitivity to smell, increasing dopamine—the neuron party appears to be the main driver of the munchies. You can read the complete study in the most recent copy of Nature. Next up, the researchers will have to figure out why cannabinoids make that one middle-aged mouse think everyone is secretly working for the CIA. He really needs to pull himself together.