Here's Why You Get the Munchies

By: Kyle Jaeger

Oh, the munchies. The intense, unremitting feeling of hunger your experience after smoking marijuana. It is perhaps the most well-recognized phenomenon in stoner culture—yet few understand the chemical and biological processes that make it happen.

ATTN: has examined how marijuana affects metabolism and what access to pot does to obesity rates in legal states, but the munchies deserves a separate study, and we've looked at the research in an effort to inform our readers about why smoking marijuana makes you crave, well, everything in sight.

 
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In large part, the munchies are a product of THC, the main psychoactive component of marijuana. When you smoke, THC activates neurotransmitters in your brain known as endocannabinoids, which regulate metabolism and activate hunger, among other things.

"Chemicals in marijuana, especially THC, activate this false sense of hunger when they interact with hormones like leptin, a main player in sending out hunger signals," Ryan Vandrey, a behavioral pharmacologist at Johns Hopkins, told BuzzFeed. "Then you get the munchies. If you hadn’t smoked, you probably wouldn’t have gotten hungry then or eaten as much food."

Why do you feel hunger when you're not actually hungry after smoking?

 
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But there are other processes involved in the munchies. A 2014 study published in the journal Nature Neuroscience found that THC operates on receptors in the brain's olfactory bulb, which means that smoking causes increased sensitivity to smell and taste.

Unlike the sober lab mice included in the study, those that were dosed with THC showed significantly greater interest in the bananas and almond oils that were placed before them. They continued to sniff and eat the food for much longer than those who weren't given the cannabis supplement.

 
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Another set of scientists at Yale School of Medicine looked at how marijuana use affected a cluster of neurons they thought was responsible for making you feel full. This cluster is known as POMC neurons, which are located in the hypothalamus.

A previous study showed that shutting down POMC neurons caused the mice to become morbidly obese, and the scientists figured that cannabinoids in marijuana would bind the activity of these neurons and make them fire less. At it happened, the opposite was true.

"The team discovered that when they injected cannabinoids into mice, the drug was turning off adjacent cells that normally command the POMC neurons to slow down," NPR reports. "As a result, the POMC neurons' activity leapt up. At the same time, the cannabinoids activate a receptor inside the POMC neuron that causes the cell to switch from making a chemical signal telling the brain you're full to making endorphins, a neurotransmitter that's known to increase appetite."

Thus, the mice got the munchies.

There are limitations to each of the studies—namely that they involve lab mice rather than a human subject. But all together, these studies offer a comprehensive overview of the processes that stimulate appetite. So next time you smoke, hopefully you'll carry this information with you. Share it with your stoner friends and you can discuss the complex relationship between cannabinoids and the human endocannabinoid system over a bag of Doritos.