The rapid onset of increased appetite, commonly referred to as "the munchies," after cannabis use is a real cognitive response and not just an anecdotal experience, according to a recent study conducted by researchers from Washington State University (WSU) and the University of Calgary. The findings were published in the Proceedings of the National Academy of Sciences (PNAS).
The research was led by Carrie Cuttler, director of The Health and Cognition (THC) Lab at WSU, along with Ryan McLaughlin, a professor at WSU's College of Veterinary Medicine. Their work was complemented by Calgary researchers Matthew Hill and Catherine Hume, who carried out parallel studies using rats.
In the human clinical trial, 82 adults between the ages of 21 and 62 from Pullman, Washington participated. Each volunteer was randomly assigned to vape either 20 or 40 milligrams of cannabis or a placebo.
"The human study found irrespective of body mass index, time of last food consumption, sex or how much cannabis was consumed, human participants who used cannabis during the trial ate significantly more food," McLaughlin said.
Participants were given access to various foods ranging from carbohydrates to proteins and fatty snacks. Some foods were more popular than others among those who had consumed cannabis.
"Beef jerky was one of the No. 1 things intoxicated people gravitated toward, which I don't understand. Honestly, I would have thought chocolate, chips, Rice Krispies treats - things like that," Cuttler said. She also noted that water ranked high on their list.
Similar patterns emerged in rat studies at the University of Calgary. Rats exposed to cannabis in controlled settings consistently worked for food rewards regardless of their fullness.
"The sober animals are kind of like, 'I'm full. Why do I care?' They don't put in any effort at all. They barely work in any capacity to get access to food. But you get them stoned again, and even though they're now full and they've eaten, they go right back as if they're starving," Hill said.
Food preference did not seem to play a role in either humans or rats under the influence.
"The same thing we saw in the humans we saw in the rats. We kind of thought it would make them want to eat carb-rich foods, but that didn't seem to be the case. It just seemed to be any food," Hill said.
The study sheds light on underlying physiological mechanisms involved in appetite stimulation related to cannabis use. Endogenous cannabinoids—also known as endocannabinoids—are produced naturally by the body and regulate functions such as mood and appetite.
"That's what the natural endocannabinoid system does in the hypothalamus," McLaughlin explained. "But THC hijacks that entire system. So even though you're not necessarily hungry, THC can stimulate cannabinoid receptors in the brain and make you feel hungry."
Further experiments indicated that blocking cannabinoid receptors specifically in the brain reduced this increased appetite response among rats; blocking similar receptors elsewhere did not have this effect.
"That's what really gives us the opportunity to look at whether this is something brain-mediated or gut-mediated, and this generally shows 'the munchies' are mediated by the brain," McLaughlin said.
Researchers hope these insights will help guide future therapies for individuals dealing with appetite loss due to medical conditions or treatments.
"There's very little documentation of the munchies phenomenon, but this paper really starts to tap into some of the mechanisms that might be responsible," Cuttler said.
