The phenomenon known as “the munchies” is common terminology among cannabis users. However, a recent clinical study now provides evidence that this effect is real and appears to begin in the brain.
Researchers at Washington State University and the University of Calgary recently published a study in Proceedings of the National Academy of Sciences showing that cannabis use led to a measurable increase in food intake among human participants, regardless of body weight, sex, or when they last ate. Parallel experiments in rats produced similar results and helped identify the underlying biological mechanism.
Testing Appetite in Humans
The human trial involved 82 adults aged 21 to 62 from the Pullman, Washington, area. Participants were randomly assigned to vape either 20 milligrams or 40 milligrams of cannabis or a placebo. Following administration, they were given access to a variety of foods and allowed to eat as much as they wished.
Participants who received cannabis consumed significantly more food than those in the placebo group, regardless of body mass index, time since their last meal, or the dose administered.
“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,” said Ryan McLaughlin, a professor in WSU’s College of Veterinary Medicine and co-author of the study.
The increase in appetite was not limited to a particular type of food. Participants selected a range of options, including protein-rich foods such as beef jerky, snack foods, and water.
Rats Show the Same Pattern
To investigate the biological basis of this effect, researchers at the University of Calgary conducted similar experiments in rats. The animals were exposed to cannabis in a controlled setting and could obtain food by pressing a lever.
Rats exposed to cannabis continued to seek out food even when they were already full. In contrast, rats that had not received cannabis showed little motivation to obtain additional food once full.
“The sober animals are kind of like, ‘I’m full. Why do I care?’” said Matthew Hill, one of the Calgary researchers. “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.”
As in the human study, the specific type of food did not influence the outcome. Cannabis increased general food-seeking behavior rather than promoting a preference for any particular category.
A Brain-Mediated Effect
The researchers also investigated whether the increase in appetite was driven by processes in the brain or the peripheral nervous system.
Endocannabinoids are natural compounds in the body that help regulate appetite through receptors in the hypothalamus, a region of the brain involved in hunger and energy balance. THC, the primary psychoactive compound in cannabis, activates these same receptors.
When cannabinoid receptors in the rats’ peripheral nervous system were blocked, appetite remained elevated. However, blocking these receptors in the brain eliminated the effect.
“That’s what really gives us the opportunity to look at whether this is something brain-mediated or gut-mediated,” McLaughlin said. “And this generally shows ‘the munchies’ are mediated by the brain.”
Implications for Appetite Loss
Loss of appetite is a common problem in conditions like HIV/AIDS, cancer treatment, and other wasting syndromes. While cannabis has often been used informally to boost appetite, scientists have known little about how it works.
“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,” said Carrie Cuttler, a WSU psychology professor who directs the Health and Cognition Lab.
This study looked at short-term changes in appetite in a controlled setting. It did not assess long-term weight gain or effects in people with chronic illness. Still, the findings provide new evidence that cannabis reliably increases food intake and does so through brain-based pathways.
As research into the therapeutic uses of cannabinoids continues, understanding how THC influences hunger circuits may help guide treatments for individuals experiencing appetite loss. These findings also help clarify one of the most widely recognized effects of cannabis.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds a Master of Business Administration, a Bachelor of Science in Business Administration, and a Data Analytics certification. His work combines analytical training with a focus on emerging science, aerospace, and astronomical research.